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A very good dictionary of common and some uncommon
The Modem Dictionary
(C) Copyright 1993 R. Scott Perry
All Rights Reserved
Version 1.50
"What is this, why, and who is this guy?"
I feel that this dictionary fills a major void. In my years
of using BBS's, I have never seen such a dictionary. The closest
thing I've seen was a text file that had about 40 words listed.
These words included "RAM" "ROM" "Microcomputer" "Telex" and a
bunch of other words that aren't really that important to under-
stand computer telecommunications. I've seen some books about
"modeming" in bookstores, but they tend to be expensive ($15-
$49), and I don't recall seeing any dictionaries of terms relat-
ing to modems. Also, many terms are easy to confuse and it can
be very difficult to find definitions for these terms. I have
seen terms used incorrectly in advertisements by modem manufac-
turers and in many magazine articles. I hope that this diction-
ary can be used as a good source of reference for confusing
terms.
Why do I feel qualified to write a dictionary such as this?
I bought my first modem more than seven years ago and have been
using computers for twice as long. Not only have I used many
different computers and modems, I have seen the days where
1200bps BBS's were rare because most people had 300bps modems.
For about a year I ran my own BBS, which was quite successful at
the time. While I only had about 150K of storage for messages
and files, I was able to get over 500 users in that year. I have
also gathered, read, and searched through hundreds of text files,
magazines, and program documentation, just to help define words
and find new words for this dictionary. I have also spoken to
representatives of major companies to help find out the truth
behind the more confusing terms.
LEGAL STUFF
This dictionary is provided with no warranty of any kind.
The author and/or distributor will not be liable for any conse-
quences resulting from the use of this information. This is a
field where misconceptions abound. Although to the best of our
knowledge all information is accurate, we can not guarantee its
accuracy.
NOTES
Note 1: It was difficult to decide what words to include and
what words not to include. I tried to include every term relat-
ing to computer telecommunications that the average user needs to
know, or might come across and be curious about. Some words
(such as PSK) are easily found in manuals for modems, but are
hard to find definitions for. I tried to include as many of
these as possible.
Note 2: Since there are so many words defined here, and many of
them are complex and easily misunderstood, I wouldn't be sur-
prised if there are a couple errors of some sort. I tried to be
as careful as I could, but it is possible that there may be some
mistakes. If you notice any mistakes, or have suggestions of
words to add (or take out), feel free to write to me. I'll
correct any mistakes in future versions.
MAKING COPIES OF THIS DICTIONARY
This dictionary is being marketing as freeware. It is copy-
righted, and you may not make any changes to it without my per-
mission.
O You may give copies to anyone you know.
O Any BBS may have this dictionary available for downloading.
O Any shareware distributors (including CD-ROM developers) may
distribute this. I'd really appreciate a note saying that you
are doing so.
O If you SELL any communications products, and wish to distribute
this dictionary with your product(s), you MUST get my permission
first (if you do not, it is considered copyright infringement).
Send requests to the address listed below.
O If you wish to QUOTE this dictionary in any media, such as in
an article for a computer magazine, you must let me know. Just
send a note to the address below.
PAYMENT?
I've obviously put in countless hours over the past 4 years
creating this dictionary. Just searching through new articles
and information to find new words takes hours.
As mentioned above, this dictionary is being marketed as
freeware. Feel free to use it as much as you want. If you find
that you are benefiting from it, I'd appreciate something. A
letter of thanks or some input would be very welcome.
I'd love to hear how you are using this dictionary. Since
its first release in 1989, the dictionary has been used: in
training courses run by modem manufacturers; as a reference for
term papers for school; as a reference for an article for a Bar
Association; by SysOps for new user messages; and more.
"How do I reach the author?"
I appreciate your input. If you notice an error, or a word
that is not included, or have praise/complaints, want to let me
know how you are using the dictionary, or for any other reason,
feel free to write to me. I'm always looking to improve the
dictionary. Send any comments/suggestions/notices/etc. to:
R. Scott Perry
178 Morton Street
Newton Centre, MA 02159
Hopefully, at some point there will be a BBS to call to get the
latest version of the Telecommunications Dictionary, as well as
to use as an easy way to contact me. Until then, you can get
the latest version from Computerized Horizons. You can write
to them at 2490 Black Rock Turnpike #309, Fairfield, CT 06430.
I hope you enjoy this dictionary!
Notes about the entries
----- ----- --- -------
* [Also called <entry>] and [Same as <entry>] mean that there are
more than one word for a certain concept. Do not bother looking
at <entry>, it will just refer you back to the original entry.
* [See also <entry>] at the end of a definition refers you to
more information or an entry that may help you understand the
original entry better. Also, a word and it's opposite will often
refer to each another.
* [See <entry>] appearing directly after the term indicates that
the definition is the same as <entry>, and you should look there.
* BBS is used here generically to denote any service that you can
call up with your computer, whether it is a bulletin board, a pay
service, or even a mainframe.
* Some entries refer to computers in general, but an understand-
ing of them is sometimes needed to understand other entries.
The Dictionary
--- ----------
---Numbers---
8N1 - The most common modem format. [See also format].
42A Block - This is a box about two inches square, with a modular
jack, that separates the wires coming from the phone company.
You can plug a phone or modem into this jacking, using a modular
cord. [See also modular cord, modular jack, modular plug].
103 - Officially, `Bell 103' which is the standard controlling
transmission at 300 bps in the United States. It was created by
AT&T. [See also 212A, V.21].
212A - Officially, `Bell 212A' which is the standard controlling
transmission at 1200 bps in the United States. It was created by
AT&T. [See also 103, V.22].
300 bps (baud) - A transmission speed that is now almost never
used, although most modems will allow communication at the speed
(since it was common in the early 1980's). It is roughly equal
to 30 characters per second.
1200 bps (baud) - In the mid 1980s this was the most common
transmission speed, until 2400 bps became popular/cheaper. It is
roughly equal to 120 characters per second.
2400 bps (baud) - A fairly high-speed transmission speed that
towards the end of the 1980s gained popularity. It is roughly
equal to 240 characters per second.
3400 hertz - The highest pitch that a telephone line will trans-
mit. This cutoff limits the ways in which computers can communi-
cate over telephone lines.
8250 UART - The UART used for the communications ports on most
older computers. [See also UART].
9600 bps (baud) - This, along with 14,400 bps are the 2 standard
speeds for high-speed modems. It can transmit and receive ap-
proximately 960 characters per second (without compression).
14400 bps - Currently, the fastest standard speed for high-speed
modems.
16450 UART - The UART used with some 286 computers. [See also
UART].
16550 UART - This is the UART used with most newer computers and
high speed modems. There are several variations, but they all
include one main feature: they include buffering, so that if data
comes in or is sent faster than the computer/modem can accept it,
the UART will hold the data (up to 16 bytes) until the
computer/modem is ready for it. [See also UART].
16550A UART - See 16550 UART.
16550AF UART - See 16550 UART.
16550AFN UART - See 16550 UART.
---A---
abort - [1] The command word used with editors that allows you to
exit, destroying your message. [2] The character used to stop
characters from a block of text appearing on your screen. Usual-
ly the spacebar or CTRL-X are used to abort a message.
access - Refers to an intangible amount (usually represented by a
security level or flags) that indicate to what extent you are
allowed to use a BBS. When used in a term such as `you will be
granted access', it means the amount of access that new users
will generally receive.
account - A term that refers to information that a BBS has about
you. It is usually referred to by an ID number or your name.
The information it contains can include any information that you
have at some point given the BBS, usually including your name,
phone number, and security level. [See also user number].
account number - See user number.
Acculink - A packet switched network that is used to save money
on long-distance telecommunications.
ACK - A character (CTRL-F) that ACKnowledges something, usually
that a certain amount of data has been received correctly. [See
also NAK].
acoustic coupler - This was common many years ago, but rare now.
It is a cradle in which you would place the handset of a phone.
This would be connected to a modem, and the modem would access
the phone line through this coupler. Modern modems connect
directly to the phone line. [See also acoustic modem].
acoustic modem - A modem that uses an acoustic coupler. [See
also acoustic coupler].
adaptive data compression - See ADC.
adaptive dialing - When a modem can determine whether to dial
pulse or tone. It will try dialing with tones first. If that
doesn't work, it will dial pulse.
adaptive equalization - Modems that have this feature "listen" to
the phone line to find the bandwidth with the least noise, and
use that part of the band for transmission. This allows for less
interference from noise.
ADC - Adaptive Data Compression. A method of data compression
developed by Hayes, with a possible compression ratio of 2:1.
alias - A name that users can use on a bulletin board that is not
their own. Aliases are usually used by young BBS users and those
who pirate software or do other illegal activities. Some exam-
ples of aliases are `Cracker Kid', `Starbuck', and `Midnight
Killer'. [Also called handle]. [See also user name].
ampersand - A character (&) that usually means `and'.
analog - As far as electronic signals are concerned, analog
refers to signals that can represent an infinite range of num-
bers, as opposed to digital which can only be distinct whole
numbers. Analog data often comes from measurements. The sound a
modem makes over the phone is analog since it can be any of a
number of different frequencies. [See also digital].
anonymous - Refers to a message, where the author was able to
leave out his name. On some BBS's you are allowed to post anony-
mous messages so that others won't know who you are. The SysOp
usually can find out who the author is, however.
ANSI - ANSI is an organization that sets standards. ANSI graph-
ics, however, is a set of cursor control codes which originated
on the VT100 smart terminal. Many BBS's use these codes to help
improve the sending of characters to communications programs. It
uses the escape character, followed by other characters, which
allows movement of the cursor on the screen, a change of color,
and more.
answering computer - This is the computer that is being called.
Therefore, it is usually the BBS or mainframe. [See also origi-
nating computer].
answering machine - See voice mail.
answer frequency - The frequency of the carrier that a modem uses
when it has been called by another computer. [See also originate
frequency].
answer mode - When a modem is ready to pick up the phone when it
rings. After picking up the phone, the modem will attempt to
make a connection with another modem. All BBS's are in answer
mode. [See also originate mode].
apostrophe - The character '. It is usually used in contractions
of words, such as "don't".
ARC - When a filename has the extension ARC, it means that it is
an archive that has been compressed with the program PKARC. To
get the files out of the archive, you need to use the program
PKXARC. You should be able to find this program on many BBS's.
[See also archive, unarchive].
archive - [noun] A group of programs that are together, usually
compressed, in one file. [verb] the process of combining those
files. There are a number of software packages which will com-
press files into an archive, and most programs on BBS's have been
archived with one of these software packages. [See also unar-
chive, compress, ZIP, ARJ, ARC, PAK, LZH].
area code - The 3-digit number used by the telephone company to
designate a geographic area. Each state in the United States has
1 or more area codes. If you call a phone number in a different
area code, you must dial "1" and then the area code before the
phone number. If you call a number within your area code, you
just dial the phone number (if it is long distance within your
area code, you must dial "1" and then the number).
ARJ - [1] A file extension that indicates that the file was com-
pressed with the program ARJ. [2] The program ARJ, used to
archive and un-archive files with the ARJ extension. [See also
archive, unarchive].
ASCII - An acronym for American Standard Code of Information
Interchange. It uses 7 bits to represent all uppercase and
lowercase characters, as well as numbers, punctuation marks, and
other characters. ASCII often uses 8 bits in the form of bytes
and ignores the first bit. [See also EBCDIC].
ASCII transfer - When a text file is sent directly as it is,
without any special codes.
asterisk - The character *.
asynchronous communication - This is when the beginning and end
of each byte that is sent over the phone lines is marked somehow.
This way, if there is line noise, the modem can find out right
away where the next byte should start. [See also synchronous
communication].
AT command - Any instructions sent to a modem that begin with
"AT". See also Hayes AT command set.
AT command set - See Hayes AT command set.
at sign - The character @. Often read as 'at'.
AT&T - American Telephone and Telegraph, the inventors of the
first modem.
attended mode - This is the mode that a communications program is
in while you are operating it. [See also unattended mode].
attention characters - The letters "AT", which get the modem's
attention that you are about to send it a command. [See also
Hayes AT command set].
audio monitor - A speaker that is included as part of a modem.
It allows you to listen to whatever sound is on the phone line.
This is often used to let you hear busy signals or make sure that
the other modem picks up the carrier.
auto-answer - When a modem has the ability to automatically pick
up the phone when the phone rings and then attempt to connect
with another computer.
auto-answer LED - When this LED (found on some external modems)
lights up, it means that the modem is ready to answer the phone
when the phone rings (it will then try to connect to another
modem). If it is not lit, the modem will not answer the phone.
[See also LED indicators].
auto-baud detect - The ability of a modem to change to a lower
bps rate if the computer it is calling is unable to communicate
at the requested speed.
auto-dial - When a modem is capable of dialing a phone number, so
that you don't have to dial manually. Almost all modems have
this ability.
auto-download - The feature of some file transfer protocols
whereby a BBS can automatically make your communications program
start a download or upload (if your communications program has
this capability too). This saves some time for the user, who
would otherwise have to set up his program to upload or download.
auto fall-back - See fall-back.
auto-kill - A feature on some BBS's that will delete a message on
a board if a certain threshold limit is reached. For example, a
BBS might delete the second message on a board if there are
already 100 messages and someone posts another message. This
would limit the board to 100 messages, but still keep the first
message (which is usually left by the SysOp).
auto-redial - A feature that allows a modem or a communications
program to dial a number again after it finds out that the number
is busy. This is very handy when trying to get through to popu-
lar bulletin boards that are often busy.
auto-reliable - The ability of a modem to be able to communicate
both with modems that do have error-control and/or data compres-
sion, and those that do not.
auto-reply - To send a message (either public or private) immedi-
ately after reading a message on a BBS. Usually, this is used to
respond to the author of the original message.
auto-syncing driver - This is the part of a BBS program that
automatically determines the bps rate of a caller. [See also
manual-syncing driver].
auto-typing - This is when a communications program can upload
information to a BBS as if the user were typing in the informa-
tion. For example, the user might type a message into a file,
and then the communications program can send it to a BBS (which
assumes the user is actually typing the message) to post as a
message.
---B---
backdoor - A way of getting into certain BBS's and getting full
access, without using a regular account. Usually the author of
the BBS program built the backdoor into the program so that he
could get access to any BBS running his software. Backdoors are
less common today than they used to be.
background send/receive - The ability of a fax/modem to send or
receive faxes while the computer is being used for other pur-
poses.
backslash - The character \.
backspace - The character (CTRL-H) that causes the cursor on your
screen to move back one space. [See also destructive backspace,
non-destructive backspace].
bandwidth - A range of radio, audio, or other frequencies.
Telephone lines have a bandwidth from 300 hertz to 3400 hertz.
Since it is so limited, a modem must carefully change data into
sounds that "fit" within this range. Similar to frequency spec-
trum.
bannerware - A software program that is free to use and copy, but
advertises another program or product. [See also public domain].
batch file transfer - This is when more than one file is sent at
a time by a file transfer protocol. The user will tell the BBS
what files he wants, and then the BBS will send all the files
before the user needs to do anything else.
baud - A term referring to the speed at which modems communicate.
Technically, it is the number of changes in an electronic signal
per second. Since the number of changes used to be the same as
the number of bits sent or received per second, bps and baud are
often used interchangeably. However, there is a difference,
which is very often confused. For example, many 1200bps modems
were advertised as 1200 baud, even though they operate at 600
baud. They send out 2 bits 600 times a second, which means that
it is 600 baud. However, since it is so often misunderstood, you
can assume that when you see "baud" it means bits per second,
unless it is stated otherwise. The term comes from the scientist
J. M. E. Baudot. [See also bps, dibit].
BBS - An acronym for Bulletin Board System. Usually it is a home
computer that has a modem attached and is waiting for calls from
other computers. It can, however, also refer to commercial serv-
ices (such as CompuServe and Prodigy) and any other computers
that you can call via telephone lines. BBS's almost always allow
you to leave messages for other users. Most BBS's have programs
that you can download and use on your computer. BBS can also be
expanded more simply to `bulletin board'.
BCC - Block Check Character. This is used to help make sure that
a group of data has not been accidentally altered.
Bell 103 - See 103.
Bell 212A - See 212A.
bisync - Refers to a modem that synchronizes with an electronic
signal over the telephone lines that marks the beginning of
blocks of data. It is one of a number of synchronous protocols.
bit - A Binary digIT. It is a number in base 2 (binary), which
means that it can only be a 0 or a 1. It is used in the expres-
sion `bits per second'. [See also byte].
bitstream - BBS's and related activities. For example, you could
say that a lot of public domain programs can be found in the
bitstream.
blind dial - This is when a modem will dial a number without
waiting for a dial tone. Some long-distance telephone services
require a number to be dialed, even though there is no dial tone.
In this case, your modem should be set to blind dial.
block - A group of data bytes. For example, when downloading a
program, blocks of 128 or 1024 characters are often sent.
block check character - See BCC.
block size - This term, when used with either error control or
data compression protocols, refers to the number of characters to
be sent at one time. If error control is used, the codes are
sent immediately following this block. Typical block sizes are
64, 128, 192, or 256 characters. Small block sizes are better
when the line quality is bad (such as for long distance calls),
while large block sizes are better during good connections (such
as for local calls).
board - [1] See BBS. [2] See message base.
bps - Bits Per Second. The transmission speed of most modems is
measured in baud or bps. Bps is literally the number of bits
sent by the modem every second. [See also baud].
braces - The characters { and }. [See also left brace, right
brace].
brackets - The characters [ and ]. [See also left bracket, right
bracket].
break signal - This is a signal sent from one modem to another
that lasts for about a second. It is sometimes used to try to
clear up synchronization problems. On CCITT V.42 modems, there
are more specialized procedures involved with the break signal,
such as regarding the timing. In V.42 there are three kinds of
break signals. [See also expedited signaling, destructive sig-
naling, in sequence signaling].
browse - To go through the list of titles of messages or files on
a BBS and note which ones you want to read.
buffer - [1] (verb) To save all incoming data in memory. [2]
(verb) to temporarily save incoming data until the computer has a
chance to process it. [3] (noun) The place in memory where the
saved information is stored, as in "I have a 32K buffer."
bulk mailing - Used on a BBS when you send the same message to
more than one person. This saves you from having to rewrite the
message. [See also E-mail].
bulletin - A special message posted on a BBS, usually written by
the SysOp. In most cases all users are expected to read any new
bulletins that may have been posted since their last call.
bulletin board - [1] See BBS. [2] Sometimes same as message base.
bulletin board system - See BBS.
busy - When a bulletin board is being used by as many users as it
can handle, which is when all the telephone lines are being used.
busy signal - The sound that you hear on a phone when the phone
number you are trying to reach is in use (busy). It usually
consists of 60 cycles per minute. [See also audio monitor].
byte - A group of 8 bits. It usually represents one character.
[See also ASCII].
---C---
call back unit - A device that can be attached to the phone line
of a BBS to make it more secure. After you connect with the BBS
and tell it who you are, the device will then call your phone
number. This is used to make a very secure system to help pre-
vent hackers from invading a system. It then becomes very diffi-
cult, if not impossible, for a hacker to get into the computer
system.
caller - Anyone who connects with a BBS. It is usually used in a
phrase such as "You are caller #4328."
caller I.D. - A code that is sent over the phone lines in some
areas when a person makes a phone call. This code includes the
phone number of the person making the call. Some modems are able
to understand this signal, and let you know who is calling you
before you answer the phone.
caller log - A list of callers who have called a BBS within a
given time period. The list may also keep information such as
the bps rate of the caller. This is used so that the SysOp can
keep track of users, as well as any hackers, if they call the
BBS.
call progress monitoring - This is when your modem tells you what
is happening when you dial another computer. It will tell you
that it has dialed the number, if the number is busy, if you
connect, etc.
call waiting - A service that the phone company offers that
allows the customer to hear a special sound on the phone if there
is an incoming call while the customer is talking on the phone.
The customer can then talk with either caller. This is a nice
service unless you have a modem and call BBS's. If you are
connected with a BBS and someone else calls you, you will be
disconnected. In most areas there is a special 2 or 3 digit
number that you can dial before a phone call that will disconnect
call waiting for that call. If you have call waiting, check your
phonebook or call the phone company to find out how to disconnect
call waiting.
capital letters - See uppercase.
capture - To 'catch' text that is being sent to your computer
from a BBS and put it in a buffer or a file.
capture buffer - The area in a computer's memory where a communi-
cations program stores incoming data that is to be saved. [Also
called capture memory]. [See also buffer].
capture memory - See capture buffer.
card (peripheral) - Any computer peripheral that can be connected
directly, inside a computer. Internal modems are usually periph-
eral cards.
caret - The character ^.
carriage return - See return.
carrier - The tone that the modem sends over the phone lines
before any data is sent on it. It has a fixed frequency and a
fixed amplitude. It is then modified to indicate data.
carrier detect - The wire in an RS-232C cable that holds the
information as to whether or not the modem senses a carrier (and
therefore is connected to another computer). [Also called CD].
carrier detect threshold - A way of measuring how well a modem
can detect valid data over noisy phone lines. It is measured in
negative dBm's (decibel-milliwatts). The bigger the number (the
more negative) the better. For example, -45 dBm is better than
-40 dBm. [Same as receive sensitivity].
carrier detect LED - This LED will light up on an external modem
when it senses a carrier on the phone line. This indicates that
the modem is connected to another modem. [See also LED indica-
tors].
carrier frequency - This is the frequency which a modem uses to
transmit or receive data.
carrier loss time - The amount of time your modem will remain on
the line when the carrier is lost. It will stay on the line for
this amount of time, to see if the carrier comes back. If the
carrier does not come back, the modem will hang up the phone
line.
CB simulator - A computer service where there are multiple phone
lines (usually at least 5). The CB simulator allows all the
users to send messages to one another while they are on-line. It
usually allows you to send both public messages that everyone who
is on-line can see and private messages that only one specific
user can see.
CCITT - International Telegraph and Telephone Consultative Com-
mittee. This group, created by the United Nations, establishes
certain standards for data transmission. Their transmission,
data compression, and error control standards all begin with V,
for example V.22. To find the standards in this dictionary, look
up the standard name, i.e. V.42.
CD - See carrier detect.
character - Any letter, numeral or symbol. [See also ASCII].
character format - See format.
characters per second - The number of bytes or characters that
can be sent over the phone lines in 1 second. This is determined
by dividing the bps rate by the number of bits it takes to send
one byte (usually 10--the start bit, 8 bits of data, and the stop
bit). So, a 2400bps modem can send 240 characters per second
(2400/10). [Same as CPS].
chat - A mode that allows two or more people (almost always a
SysOp and a user on a BBS) to communicate directly with each
other using the modem. Usually, each person can see what the
other is typing at all times and can interrupt them (a beeping
sound with a CTRL-G is useful to interrupt with). [See also page
(verb)].
chat mode - This is when a communications program is set up so
that the user can "chat" with someone on the other end of the
line. One way this can work is that anything that is typed by
the other person is printed on the top half of the screen, but
anything you type would appear on the bottom half of the screen.
[See also chat].
checksum - A number that represents a larger group of numbers in
order to check for errors in data transmission. It is commonly
used when downloading a program, as well as in error control
protocols. The checksum is the result of a mathematical equa-
tion, such as adding all the numbers in a block together (al-
though it is usually more complex than that).
chip set - A group of important IC chips on a modem (or other
computer peripheral) that are all made by the same manufacturer.
While there are many companies that make modems, there are only a
few that make the chips for them. Because the chip manufacturer
is making the chips for many companies, they produce more chips,
and the price of the chips is lower than if each company produced
their own. This decreases the price of the modems on the market.
Christensen protocol - See Xmodem.
circular dialing queue - This is used in some communications
programs to allow you to enter a list of phone numbers to call,
and it will keep going through the list and dialing numbers until
it reaches one of them. This is useful if you are trying to
reach BBS's that are often busy.
city code - With many foreign countries, you need to dial a city
code before the phone number you are trying to reach. You must
dial the country code before the city code. The city code will
be from 1 to 5 digits. [See also country code].
clear to send - See CTS.
columns - A measurement of the width of your screen as measured
by the number of characters your screen can fit across it. BBS's
often ask for your screen width. Most computers have a screen
width of 80 columns.
COM port - IBM and compatible computers have the ability to hook
up devices (such as modems and mice) to the computer, through
ports. These ports are called COM ports, and are numbered 1-8.
While all 8 could be used, usually only #1 and #2 are used, while
#3 and #4 are used occasionally. [See also selectable COM port].
comm program - See communications program.
command buffer - The place in your modem's memory where it stores
the commands that you give it. [See also buffer].
command echo - When this is on, any AT command sent to the modem
will then be sent back from the modem to the computer. For
example, if you were to type "ATS11=40," the modem would act on
the command, and then send "ATS11=40" back to the computer.
command mode - This is when your modem interprets what you type
as commands, rather than just sending the data over the phone
line. [See also data mode, terminal mode, voice mode].
command set - A list of all the possible commands that you can
give something, such as a modem, a BASIC program, or a BBS. [See
also Hayes AT command set].
commands - Instructions that you can give to a modem, a BBS, or
another similar device.
commercial host system - An on-line system that you can call up,
that is operated by a company that charges you to use it.
commercial software - Software that is copyrighted and may not
legally be distributed by BBS's or copied and given to other
users. [See also public domain, copyright].
communication - The idea of transferring one's thoughts or ideas
to another person. This can be through speaking, radio, T.V.,
telephones, mail, etc.
communications program - A program that controls a modem, and has
features that allow the user to do such things as upload, down-
load, etc. It is similar to a terminal program but more sophis-
ticated. It used to be used interchangeably with terminal pro-
gram. [Same as comm program].
compatible - When one object can work just like another. Al-
though the term is usually used with computers, it is often used
with modems. Many modems are compatible with other popular
modems. [See also V.42 compatible].
compliant - See V.42 compliant.
compress - To make data take up less space. Archiving programs
do this, which means that files will take less time to transfer
with modems. Many modems now have the ability to automatically
compress the information they send and receive. [See also ar-
chive, data compression].
compression ratio - The ratio of the original size of data that
is sent to the compressed size. For example, a 3:1 compression
ratio means that the original data takes up 3 times the amount of
space as the compressed data, and a modem would transfer the data
3 times more quickly than if it was not compressed.
computer network - See LAN.
configure - To set something to your liking. To configure a BBS,
you may have to tell it your screen width, whether you need line
feeds and other such information.
configuration - Configuration is the information describing what
your computer's hardware and software is like, so that a BBS can
send information properly. For example, you need to tell a BBS
how wide your screen is.
connect - [1] To get to a point where you can start communicating
with a BBS, as in "I have connected with the BBS." [2] Any point
after you have established contact with a BBS, as in "I am still
connected with the BBS" or "I have been connected with the bulle-
tin board for just over an hour."
connect speed - The speed, in bps, which your modem uses when it
connects with a BBS. This speed will depend on the speed of your
modem, and the BBS's modem. It will be no higher than the lower
of the two speeds. If you have a 2400bps modem, and call a
1200bps BBS, your connect speed should be 1200bps.
connection - The actual contact with a BBS. It is used most
often in expressions such as "I have a bad connection," meaning
that there is line noise.
control character - Any of the 32 ASCII characters that do not
print on your screen or printer. These characters are usually
used to control your computer. [See also CTRL].
copyright - A term meaning that a program or text file is pro-
tected by the government so that it may not legally be copied,
except to make backup copies, or as specified by the author of
the program. You should not upload a copyrighted program to a
BBS, unless it is shareware or freeware. [See shareware, free-
ware].
Co-SysOp - A term similar to a vice president. The Co-SysOp of a
BBS has more access to the BBS than any other user except the
SysOp. The Co-SysOp might check messages to make sure that they
are suitable for the BBS (not containing illegal messages), and
he may be able to validate users. Sometimes a Co-SysOp is just a
title given to someone who helped the BBS a lot by doing things
such as posting messages and uploading. Also, many times there
is more than one Co-SysOp. [See also SysOp].
country code - The code that the telephone company uses to desig-
nate a certain country. If you need to call a BBS (or a person)
in a foreign country, you need to dial the country code, then
usually the city code, and then the local phone number. The
country code will be 2 to 3 digits. [See also city code].
CPS - See characters per second.
<CR> - Carriage Return. See return.
CRC - Stands for Cyclic Redundancy Check. CRC is a system to
make sure that a block of data (usually from a downloaded pro-
gram) is as free from error as possible. It is usually 16 or 32
bits long (CRC-16 and CRC-32 respectively).
crash - When a BBS is harmed in such a way that it is temporarily
inoperable. The usual cause is that some files are destroyed,
either by accident or by a hacker. Some people try to crash
BBS's, a fact that most users (and especially SysOps) think is
sad.
crash recovery - This feature of some file transfer protocols
allows a user to continue a download or upload that had been
interrupted. With this system, a user will not have to receive
the data that had already been sent before the disconnection,
which will save time.
crippleware - This is software, usually distributed as shareware,
but it is not a complete program. If it is a game, it might only
let you play the first level. If it is a database program, it
might only let you have 50 entries (whereas the real version
would have more).
CRT - Cathode Ray Tube. This is another name for a computer
monitor.
CTRL - The abbreviation for ConTRoL. This abbreviation is fol-
lowed by a dash and then a character, such as CTRL-C, meaning the
control character C. [See also control character].
CTRL-G - The control character G, which usually causes the com-
puter to produce a beeping sound.
CTS - Clear To Send. This is when the modem lets the other
computer know that it can send information to the other computer.
[See also flow control, RTS].
CTS/RTS - The method of flow control that uses the CTS and RTS
signals. It is built into the hardware, not software. [See also
CTS, RTS, flow control].
cursor - The marker that points out where text will next appear
on your screen. It can be one of many things, usually a plain
white or flashing square, or an underline character.
cyclic redundancy check - See CRC.
cycling - When a light (such as the RD light) on an external
modem continuously turns on and off.
---D---
dash - The character -.
data - A group of characters that represents meaningful informa-
tion. This information can be anything, ranging from bank ac-
count numbers to computer programs. [See also information].
database - [1] A program that keeps track of data, such as the
information contained on mailing labels, or the price of stocks.
[2] A large group of data. The sum of the information that you
can receive on extensive pay services such as CompuServe can be
considered a database.
database hack - A way that hackers attempt to gain access to
someone's account on a BBS. They create a list of common pass-
words (such as SECRET and MINE) and try every one on an account
to see if it is the right password. Because of this, an intelli-
gent BBS user will not use easy-to-guess passwords.
data bits - [1] The number of bits that the modem uses to repre-
sent one byte. This is usually 8, though it can be 7 since ASCII
needs only 7 of the 8 bits. [See also format]. [2] the actual
bits within a byte being sent through the phone lines.
data byte - A byte of information that is being sent over the
phone lines.
data carrier detect - See DCD.
data communications equipment - See DCE.
data compression - Some modems have the capability to 'squash'
data so that it takes up less space. When another modem (that
also has this capability) receives the data, it 'unsquashes' the
data to its original form. By using data compression, a modem
can send information faster. It's a lot like shorthand--all the
information is still there, but it takes less space and is quick-
er. [See also MNP-5, V.42bis].
data grade - A phone line that is set up by the phone company to
be more convenient for data communications. It should have
better electronic characteristics than a regular phone line.
[See also voice grade].
data mode - The mode that a modem is in where all information
typed on the computer will be sent through the modem, and all
information received by the modem will be placed on the screen.
[See also command mode, terminal mode, voice mode]. [Same as
on-line mode].
data modem - A modem that does not have the ability to send or
receive fax transmissions.
data rate - See data transmission rate.
data set ready - See DSR.
data terminal equipment - See DTE.
data terminal ready - See DTR.
data throughput - See effective transfer rate.
data transmission rate - The speed at which data travels. For
example, data may be sent at 115,200bps. [Same as transmission
rate, transmission speed, data rate]. [See also bps].
dB - See decibel.
dBm - Decibel referred to one milliwatt. This is used to measure
certain levels, such as transmit level. [See also transmit
level, receive level, carrier detect threshold].
DB-25 - The 25 pin plug that connects an RS-232C cable to the
RS-232 port.
DCD - Data Carrier Detect. This tells the computer whether or
not the modem is connected to another modem.
DCE - Data Communications Equipment. These are computer periph-
erals that communicate. A modem is a DCE. [See also DTE].
decibel - A unit describing how loud one sound is compared to
another. [Same as dB].
decompress - The process of converting compressed data back to
its original form. [See also archive].
decoy program - A program or text sent on mainframes and multi-
line BBS's that simulates the log-on procedure. The unsuspecting
user will see this and enter his password, and the person who
made the decoy program will get the password and can use the
account.
default - A setting or an answer to a question that is automati-
cally assumed. If 80 columns is a default, then you only have to
change it if you want something other than 80 columns.
delay time - The time it takes between sending data on a computer
and receiving a response from the remote computer. If the delay
is long, most file transfer protocols will slow down. [See also
protocol].
demodulate - To convert the tones that a modem sends over the
phone lines back into data. [See also modulate].
destructive backspace - A term that indicates that your communi-
cations program deletes the character the cursor is on when it
receives the backspace character. [See also non-destructive
backspace].
destructive signaling - This is a type of break signal that
causes all data to be destroyed while the break signal is being
sent. [See also break signal].
dial - To send out either the tones or pulses that the phone
company needs to understand what number you are calling. Most
modems will dial automatically (auto-dial).
dialing speed - See touchtone dialing speed.
dialout facility - A service where you call a computer, and from
that computer you can call other computers. It is usually used
with packet switching networks, which saves you money on long
distance calls.
dialup line - A telephone line connected to the telephone compa-
ny. This is a regular phone line. [Compare to leased line].
dialup modem - A modem that is used over normal (dialup) tele-
phone lines.
dial modifiers - Any commands that are sent to a modem which
change the way a phone number is dialed. For example: tone,
pulse, and pause.
dial tone - The sound that you hear when you pick up the phone if
it is ready to have an outgoing call made. Your modem, if it can
dial, should understand this tone.
dibit - Two bits sent simultaneously by a modem. For example, a
modem can operate at 1200bps and 600 baud. What happens in this
case is that 600 times a second, the modem sends out a dibit (two
bits). Therefore, it is sending 1200 (600 times 2) bits per
second. [See also bps, baud].
dictionary - The V.42bis data compression protocol stores certain
data that is being sent/received in a "dictionary," which it
refers to when compressing/decompressing data. [See also
V.42bis, dictionary size]. [Same as encoder dictionary].
dictionary size - This is the number of characters in the dic-
tionary used for the V.42bis data compression protocol. It is
usually 2048, but can also be 1024, 512, or 4096. [See also
dictionary, V.42bis].
digital - A system using discrete numbers to represent data. In
computer systems, these are the numbers 0 and 1 (for binary).
[See also analog].
digital signal processing - This is what is used to perform echo
cancellation on a CCITT V.32/V.42 modem. [Same as DSP]. [See
also echo cancellation].
DIP switch - DIP stands for Dual In-line Package. DIP switches
are a group of small switches placed together on electronic
equipment. Many modems have these. The switches can be changed
to alter various settings. For example, one DIP switch on a
modem may change the status of the DTR.
direct mode - See MNP direct mode.
disconnect - To hang up the phone and cause the connection be-
tween your modem and another computer to be stopped. Most BBS
programs have a way of disconnecting a user who has called the
bulletin board, if it is needed.
disk capture - This is when a communications program will save
incoming information to the disk. This is useful if you are
receiving a text file that you want to read later.
dither tone - See echo suppressor defeat tone.
door - A gateway that will allow a bulletin board to run a pro-
gram while a user is on the BBS. Games are popular doors on
BBS's, although doors can be used for serious purposes, too.
down - A word meaning that a bulletin board is not working, so
that you can not connect with it. This can mean that there was a
crash, or it could simply mean that the SysOp is playing a game
on his computer. Often a SysOp will leave a phone connected to
his BBS line off the hook when he is using the computer so that
you will get a busy signal. [See also running].
download - To receive a computer file from a bulletin board. It
is usually a computer program, but can also be a text file. [See
also upload, protocol].
DSP - See Digital Signal Processing.
DSR - Data Set Ready. This indicates that the modem is on, and
ready to accept input from the computer (either commands or data
to be sent over the phone line). [Same as modem ready].
DTE - Data Terminal Equipment. This is computer equipment which
is not directly responsible for communicating, for example, the
computer itself and printers. [See also DCE].
DTMF - Dual Tone Multi-Frequency. This is used in tone dialing.
It is a method where 2 distinct tones are sent for each digit
dialed.
DTR - Stands for Data Terminal Ready. The DTR signal is sent
from the computer to the modem, to let the modem know that the
computer is ready to communicate.
dumb modem - A modem that only sends and receives characters to
or from the phone line. [See also smart modem].
dumb terminal - A keyboard and monitor that receive and send
information either to or from another computer or a phone line.
It is up to the other computer to do anything else, such as word
wrap. [See also terminal, smart terminal].
duplex - The capability of both sides of a connection to send
information at the same time. Full duplex is the same as duplex.
When you are talking on the telephone to someone you are using
duplex (you can both talk at the same time if you want to). [See
also half duplex].
---E---
EBCDIC - Stands for Extended Binary-Coded Decimal Interchange
Code. It is a way of coding characters. It is similar to ASCII,
but it uses 8 bits instead of 7. [See also ASCII].
EBBS - Electronic Bulletin Board System. See BBS.
echo - [1] A character that is sent back from a BBS instead of
the character that was sent to the BBS. For example, if you
enter your password on a BBS it will often say `dots will echo',
meaning that it will send a period for every character in your
password (it is a safety feature). [2] When a bulletin board or
your terminal program sends back the characters that you type.
If the bulletin board does not send back the characters, your
terminal program should print them to your screen as you type
them. [3] Echo on the phone lines is when you hear an echo on a
long distance call. This can interfere with modem transmissions.
[See also local echo, echo suppression].
echomail - This is a technique used by many BBS's that will allow
a message base to be shared by many BBS's. Usually late at night
the BBS's will exchange any new messages. This way a user on one
BBS can interact with users on other BBS's.
echo canceling - This is included in the CCITT V.32 standard. It
attempts to cancel echoing on long distance calls, which other-
wise would interfere with the transmission. It sends the exact
opposite of the sound it receives, which cancels the echo. [See
also echo suppression, digital signal processing].
echo suppression - Echo suppression is a technique that the phone
company uses in an attempt to make long distance voice calls
sound better, by minimizing echo. However, this can cause the
carrier of a modem to be lost (or at least garbled, causing a
loss of data). In order to prevent this problem, a modem needs
to send a certain tone over the phone line at all times. [See
also echo suppression defeat tone].
echo suppression defeat tone - This is a signal sent over the
phone lines by some modems in an attempt to cancel out the nega-
tive effects of echo suppression. In the Bell standard, it is
2225Hz +/- 10Hz, in CCITT standards it is 2100Hz +/- 15Hz. [Same
as dither tone]. [See also echo suppression].
editor - The part of the BBS that allows you to enter a message
and edit it.
effective throughput rate - See effective transfer rate.
effective transfer rate - This is the rate at which data can be
sent after data compression has been accounted for. For example,
a modem may be rated at 9600bps. If it uses data compression
with a ratio that averages 2:1, it has an effective transfer rate
of 19,200bps. While only 9600 bits are sent over the phone line,
they represent 19,200 bits of real information after they are
decoded. [Same as throughput, data throughput, effective
throughput rate]. [See also raw speed, data compression].
EIA - Electronics Industry Association. They developed the RS-
232C standard. [See also RS-232C].
electronic mail - See E-mail.
E-mail - Electronic mail. Messages that are sent to individual
people. You choose who to send the message to and only that
person receives the message. (Some BBS programs allow you to
send bulk E-mail, which goes to more than one person, but the
concept is still the same.)
emotion icons - These are groups of several characters that are
used to express emotion over the phone line. For example, :) is
a happy face (when you look at it from the side). Similarly, :(
is a sad face.
emulate - When a communications program imitates a certain brand
of terminal.
encoder dictionary - See dictionary.
encryption - Coding data so that people who are not supposed to
see the data will not be able to understand it.
ENQ character - This is the same as Control-E, ASCII value 5. It
stands for Enquiry.
EOF - Stands for End Of File. It is the character CTRL-Z, which
can mark the end of a text file.
equalization - When a modem adjusts its transmit level for dif-
ferent frequencies, to account for the greater loss at certain
frequencies over the phone line. [See also transmit level,
receive level].
error - When there is line noise and one or more characters are
changed. This is especially noticeable when downloading or
uploading a program. In this case the error must be detected,
and the data must be re-sent (or else the file will be
destroyed). [See also line noise].
error control - The ability of a modem to notice errors in trans-
mission, and have any incorrect data re-sent. [See also MNP 1-4,
LAPM, V.42].
error correction - See error control. (Error control is a more
correct term, since the modem does not correct incorrect data, it
just has it sent again).
error free - When referring to data transmission, error free
refers to communications equipment in which data is transmitted
perfectly. This is actually an impossible situation, but it is
possible to have data that is very, very close to error-free.
ESC - See escape key.
escape character - ASCII character 27. [See also escape key,
ASCII].
escape character guard time - See guard time.
escape code - See escape sequence.
escape key - The key marked ESC on a computer keyboard. It is
often used to 'escape' out of a program or procedure in a pro-
gram. Also, the ASCII character (ASCII 27) is used by ANSI to
produce limited graphics. [Same as ESC]. [See also ANSI].
escape sequence - A sequence of characters (usually +++) that
instruct a modem to change from data mode to command mode, if
they are typed with a certain delay before and after they are
typed. [See also data mode, command mode, guard time].
even parity - This indicates that the parity bit is always set
such that the sum of the "1" bits in each byte that is sent, plus
the parity bit, is an even number. [See also parity bit,
format].
executive mode - When a user is connected to a bulletin board,
but the SysOp is controlling the bulletin board. The most common
use of an executive mode is when the SysOp validates users with-
out the user having to hang up.
exit - See logoff.
expedited signaling - Break signals that are sent before any
other data. All data will remain intact. [See also break sig-
nal].
expert mode - Many BBS's have this feature, which allows a user
who feels that he knows the system well to save time by not
having menus sent to his system. If he forgets some commands
that are available, he can have the menu appear. Otherwise, the
menus will not appear. This is especially helpful at slow
speeds.
extension - The extension of a filename on an MS-DOS system is
the last three characters, which are separated from the rest of
the filename by a period. For example, the filename SPREDSHT.WKS
has the extension "WKS". [See also archive].
external modem - A modem that is located outside of the computer.
It is hooked up to the computer with a cable, most commonly an
RS-232C cable. [Same as stand-alone modem]. [See also internal
modem].
external program - A computer program that is separate from
another program. When BBS software runs a program that is sepa-
rate from it, it is called an external program. [See also door].
external protocol - This is a file transfer program that is not
built into your comm program, but the comm program is able to run
it anyway (as an external program). [See also internal proto-
col].
extract - To take out files from an archive. [See also archive,
unarchive].
---F---
factory configuration - The way that your modem was set up when
it left the factory. Typing ATZ normally returns your modem to
the factory configuration.
fall-back - The ability of a modem to change to a lower speed
when there is a problem communicating at the higher speed (usual-
ly caused by line noise). [Same as auto fall-back].
fall-forward - This is when a modem will change to a faster speed
if line conditions improve after a fall-back occurs.
fax - Short for facsimile. It is a copy of a piece of paper that
is sent over the phone lines by a fax machine. Some modems also
have fax machines built in them, so that they can send and/or
receive faxes. [See also faxmodem].
faxmodem - A modem that also has the capability of sending and
receiving faxes. [See also fax].
FCC - Federal Communications Commission. This is the government
agency that is responsible for making sure that phone lines are
being used correctly and that radio interference is at acceptable
levels.
FDM - Frequency Division Multiplexing. A way that some modems
transmit full duplex information, by splitting the telephone
bandwidth into two sections. One is used to receive data, the
other is used to send data. This method can be used at speeds of
up to 2400bps. [See also modulate].
feature negotiation - This is when a modem can determine the best
protocol to use when connecting to another modem. This includes
the fastest speed, error control, and data compression. It is
part of hand-shaking. [Same as negotiation scheme].
feedback - A message that is sent by a user to the SysOp of a
bulletin board. While it is meant to be a way for the user to
let the SysOp know of any complaints or compliments they may
have, it is more often a convenient way of sending E-mail to the
SysOp.
filter - When a communications program or a BBS program takes out
certain characters or words and doesn't accept them. For exam-
ple, a bulletin board program may filter out CTRL-G's so that the
SysOp does not hear the beeping. Also, some BBS programs have
the ability to take out obscene words from messages. [See also
profanity filter].
filter device - A piece of hardware which goes between the modem
and the phone line of a BBS. When a user calls up, they will
either have a voice or computer connection that asks them for a
special password before they can gain access to the main computer
system. This makes it more difficult for hackers to get into the
system, but is also more of a burden for the legitimate users.
flash - On a normal telephone, this is when you quickly push down
and release the off-hook button. It is often used for call
waiting. Many modems have a command that will simulate this
action.
flag - A piece of information that is either TRUE or FALSE. It
is used in some bulletin board security systems to indicate
whether the user has access to certain parts of the bulletin
board. It is also used by modems for certain indicators such as
DTR.
flow control - A method of controlling when information is sent.
One method is Xon/Xoff, where a BBS will send information until
your computer sends an Xoff (CTRL-S). It will resume sending
information when you send an Xon (CTRL-Q). [See also Xon/Xoff,
CTS/RTS].
format - Information such as "8N1" that describes the way that
your computer and a bulletin board should be connected. The
first digit is normally 7 or 8, the number of data bits. The
second character is a letter describing the parity (N for None, M
for Mark, S for Space, O for Odd, and E for Even). The last
number is the number of stop bits. 8N1 is the most common for-
mat. Data is sent as follows: Start bit (0) - 7 or 8 bits of
data - (parity bit, if used) - stop bit (1) - (gap bits, if used)
[Same as settings].
forward - To send E-mail that you received to someone else.
framing bits - Bits that are used to separate characters. The
bits themselves are not used as information. [See also stop
bits, start bits].
framing error - This occurs when the UART in a modem does not
detect a stop bit. The modems are probably out of sync with each
other.
freeware - Computer programs that are copyrighted, but they may
be legally copied if there is no payment involved. They are
almost the same as public domain programs, except that public
domain programs are not copyrighted and may be sold for payment.
Freeware programs often can not be changed when they are distrib-
uted. [See also public domain].
frequency division multiplexing - See FDM
frequency shift keying - See FSK.
frequency spectrum - A range of frequencies having similar char-
acteristics. All sounds we hear are grouped as the audio fre-
quency spectrum. Similar to bandwidth.
FSK - Frequency Shift Keying. This method that low-speed modems
use to transmit information over phone lines uses 4 frequencies,
which are used to represent 0's and 1's for both sending and
receiving. These modems can only operate up to a speed of 600bps
at full duplex (or 1200bps at half duplex). [See also modula-
tion].
full duplex - See duplex.
full flow - See streaming.
---G---
gap - See gap bits.
gap bits - A series of 0's that are sometimes sent between data
bytes over the phone lines.
garbage - Unwanted characters that appear because of either line
noise or incorrect settings. [See also line noise, format].
gateway - A connection between one network and another. For
example, on some commercial on-line services, you can reserve
airplane tickets. This usually involves the on-line service you
called connecting to the airline's computer.
general file - Any kind of text on a bulletin board that is not
specifically E-mail, a bulletin of any sort, or a message.
Usually they are long files for the user's information. Some
examples of general files are: a file containing more information
on the bulletin board program, a newspaper article about a con-
troversial issue, and an article that explains how to make your
own disk drive.
global scan - When a bulletin board goes through all the messages
on all boards to check for new messages that the user has not yet
read. This is very useful as it prevents the user from having to
go through each board to check for new messages. [See also
quickscan].
goodbye - See logoff.
group III FAX - The standard controlling fax communication.
guard time - When the escape sequence is sent to your modem, the
guard time is the amount of time that must occur between charac-
ters of the escape code, for it to be considered the escape code.
Otherwise, it will assume you are entering data that is meant to
be sent to the other modem. [See also escape code, data mode,
command mode].
guard tone - A tone that is sometimes sent over the phone line
for echo suppression. 1800 hertz and 550 hertz are sometimes
used.
guest - When a user is just looking at a bulletin board and does
not want to receive an account there. The user usually has the
same privileges as a new user who has not yet been validated.
Many bulletin board programs allow guests. This is a good fea-
ture, since the SysOp does not have to validate users who will
not be calling the board more than once or twice.
---H---
hacker - [1] A programmer who likes to experiment with computers
(this is the type of person who often will not read the documen-
tation to software before using it, so he can figure out how to
use it by himself). [2] A person who attempts to abuse the
privileges of computer BBS's and other services. His activities
may range from getting and exploring an account he is not sup-
posed to have on a mainframe computer to attempting to crash a
bulletin board. These people are unwanted by most BBS's. They
are often not malicious. The media sometimes confuses them with
phreakers. [See also phreaker].
half card - For IBM compatible computers, this is a card that is
smaller than normal (about half the size). It does not affect
the operation of the modem.
half duplex - This is a mode which allows only one modem at a
time to transmit information. When one modem is finished, the
other can then start to transmit. [Same as simplex]. [See also
duplex].
hand-shaking - The process of establishing an electronic link
between two modems. Handshaking lets both modems know informa-
tion such as the speed they will be using, and whether or not the
modems have the same type of error correction capability. [See
also feature negotiation].
handle - See alias.
hang - When a bulletin board all of a sudden starts to do noth-
ing. That is, it will not accept calls or even let the SysOp
type anything until the computer is reset. This can be caused by
a problem with the BBS software, or the computer itself.
hang up - When someone closes a switch which stops a telephone
connection. This either happens when someone puts a telephone
receiver into its cradle or when the person instructs the modem
to hang up.
hardware error control - This is when error control is performed
by the modem, not the communications program. [See also error
control].
Hayes compatible - Any modem which operates in the same way as
the modems developed by Hayes. Most modems up to 2400bps are
Hayes compatible.
Hayes AT command set - This is the set of commands used to oper-
ate Hayes modems and Hayes compatible modems. Almost all of the
commands start with AT.
help file - Many BBS systems will include information on how to
run the system in case you are having troubles. Often just
pressing "H" or a question mark at the main menu will show you
the information, but with some systems you have to find the help
file somewhere, occasionally amidst the files to be downloaded.
hertz - A unit of frequency, which equals cycles per second.
high speed - A modem that operates at a high speed. In most
cases it is assumed to be at least 9600bps.
host - The computer that is being used to store information from
other computers. Every BBS is a host, and so are pay services.
host program - A computer program that allows your computer to
accept incoming calls, and let the callers upload or download
files. It is limited compared to a BBS. If you want to do any-
thing more, such as record information or print it out, you
usually have to do the programming yourself. [Similar to unat-
tended mode].
hot-keys - A term which means that you only have to press one key
at a menu, rather than several. You don't have to hit the return
key. Usually you can do this while a menu is being sent to your
computer (so you don't have to wait for the whole menu to be
sent).
HST - High Speed Technology. A high speed protocol developed by
US Robotics. It allows for 14400bps one way, and 450bps the
other way. The two computers can switch when one has more infor-
mation to send than the other. It is not compatible with the
CCITT protocol.
hyphen - The character -.
Hz. - See hertz.
---I---
IBM graphics - On IBM computers, there is a group of "graphic"
characters (such as lines, used to make boxes) that can be shown
on the screen. Some BBS's will send these graphic characters if
requested. Most non-IBM computers will not recognize these
characters. These characters' bytes have their 8th bit set to 1.
ID number - See user number.
idle time - When a computer is not being used. This refers to
either a computer running a BBS that is not busy, or a caller
that is not sending anything or receiving anything. Some BBS's
will hang up a user if there is a certain amount of idle time
(such as a minute).
inactivity timer - When this is on, a modem will automatically
disconnect from a remote computer after a given amount of time
passes without any information sent or received.
incoming - Information that is being sent to your computer.
information - Any data that is sent between computers. Data
usually refers to numbers and small pieces of information.
Information is usually used for larger things, such as text
files. [See also data].
initialize - To set up either hardware or software to work cor-
rectly with your system. Many modems have to be initialized each
time they are used so they `know' how to act with the communica-
tions program. When your software initializes your modem, it may
tell the modem to expect 2400 baud and no parity, as well as the
fact that you do not want any information to echo on your screen.
[See also initialization string].
initialization string - This is the command that your communica-
tions program sends to the modem when the program is started. In
most cases, it is an AT command just like you would type in.
[See also initialization].
interdigit interval - When pulse dialing is used, you need a
certain amount of time free of "clicks" so that the phone company
knows when each digit is finished. When you are dialing on a
rotary phone, you don't need to worry about this because the time
it takes to turn the dial is sufficient. A modem that sends
pulse codes must wait a specified amount of time before going
from one digit to the next in a phone number. A value between
1/2 second a 1 second is usually used.
internal modem - A modem that is `hidden' inside your computer.
Outside of your computer you will only see the phone cord. An
internal modem can either be on a peripheral card that is placed
inside your computer, or it can be built into your computer.
[See also external modem].
internal protocol - A file transfer protocol that comes as part
of a comm program, and is not separate from it. [See also exter-
nal protocol].
interrupt - An interrupt, as far as modems and computers are
concerned, is an electronic signal that tells the computer that
something important is happening. Most modems can be set up by
software to send an interrupt every time a character is received
by the modem. When operating at fast speeds, this makes sure
that the computer doesn't miss characters as it is printing them
on the screen or saving them to a disk.
in sequence signaling - Break signals that are sent in the proper
order among data, as opposed to expedited signaling (which will
send the signal before other data). No data is harmed, it all
remains intact. [See also break signal].
---J---
jack - The small plastic box that your phone cord connects to on
your wall.
jump - A command used on some BBS's to go from one board or
section on a BBS to another.
jumper - This is a piece of plastic and metal that can be moved
on an internal modem to change a setting, such as the COM port to
be used. [See also selectable COM port].
---K---
K - When K is placed after a number, it means 1024 times that
number. If you computer has 640K that means that it has a little
more than 640,000 bytes of memory. Often communications software
will tell you that you have a certain amount of free memory to
use as a buffer.
Kermit protocol - An almost error-free file transfer protocol
usually used for text transfers. It was developed at Columbia
University. [See also protocol].
keyboard macro - A macro that will allow you to hit one or sever-
al keys and have the program act as though you had typed a lot
directly from the keyboard. [See also macro].
kill - When referring to a message on a bulletin board, it means
deleting that message from the board. Usually you can only
delete the messages that you write (unless you are a SysOp).
---L---
LAN - Local Area Network. This is a group of computers that are
all connected. Usually, there is one computer that controls all
peripherals (such as printers and a hard disk drive). The other
computers are linked to the controlling computer, which lets the
other computers take turns using the peripherals. [Same as
computer network].
LAPB - Link Access Procedure Balanced. This is a form of error
control found in X.32 packet switched networks.
LAPM - Link Access Procedure for Modems. A type of error control
used by some modems. It is included in the V.42 protocol
(V.42bis also includes it, since V.42bis includes all V.42 error
control methods). It is NOT a compression method, even though
some modem manufacturers have incorrectly advertised it as such.
[See also V.42, error control].
leased line - A telephone line that directly connects two comput-
ers. It is usually rented from the telephone company. A leased
line doesn't have many of the electronic restrictions that a
dialup line has, so data can be sent faster. However, data
therefore can only be sent between those two computers. [Compare
to dialup line]. [Same as private line].
LED indicators - The lights on external modems that indicate
conditions such as speed, RD, DCD, etc.
leech - A person who downloads a lot from a BBS, and does not
contribute much to the BBS by uploading programs or using the
message bases.
left-brace - The character {. It's not used often.
left-bracket - The character [.
letter - [1] The characters A-Z (uppercase or lowercase) [2]
Another term for a message posted on a BBS.
LF - Line Feed. This is a control character (ASCII 10) that is
used on some computers and printers to move down one line (on the
screen or paper). It is usually used right after a carriage
return. [See also return].
LHARC - A program that will extract archives with the extension
"LZH". [See also archive, LZH].
line - [1] A row of characters on your screen, for example, many
computers have screens with 25 lines. [See also columns]. [2]
The connection between your computer and a BBS. Most commonly
used in the term "line noise." [3] A phone line connected to a
BBS. For example, a BBS might advertise that it has "4 lines,"
meaning that 4 people can call the BBS and use it at the same
time. [Same as node].
line delay - See delay time.
linefeed - See LF.
line noise - This is interference on the telephone lines. It
will cause a character or many characters of garbage to appear on
your screen. In general, the higher the bps rate of your modem,
the more line noise will appear. However, error control proto-
cols strive to eliminate line noise (and get rid of most of it).
[See also error control].
link access procedure - See LAPM, LAPB.
local - On a computer that is running a BBS, there are 1 or more
phone lines connected to it. However, the SysOp can usually use
the BBS, too, from the keyboard. This is considered a local
connection.
local analog loopback - Tests the connection between a modem and
the computer. [See also local digital loopback].
local area network - See LAN.
local call - A phone call to a phone number in your local area,
which will not incur long distance charges. [See also long
distance call].
local digital loopback - Tests the connections between a comput-
er, the modem, the phone line, and the remote computer. [See
also local analog loopback].
local echo - This is when a communications program will send
information (either that you type or from a file) to your screen,
as well as to the other modem. Usually local echo is not used,
and the BBS you are connected to will send the information back
to you, and only then will the communications program print what
you typed on your screen.
local number - The phone number used after a country code, area
code and/or a city code. In the United States, it is 7 digits
long.
log - A log is a file that keeps track of some kind of use. In a
communications program, it might keep track of what BBS's you
call. A BBS can keep a user log, which is a file that indicates
which users called up and when. [See also user log].
logic bomb - This is part of a software program that will do
something malicious. For example, the author of a BBS program
might have the program set up so that if he enters his initials
in a certain point while the program is running, it will destroy
all of the files on the BBS. These are no longer as common as
they used to be.
logoff - To leave a BBS. When you choose to logoff, the BBS will
usually ask if that's what you really want to do, then it will
hangup. It may also ask if you want to leave a note to the
SysOp. [Same as exit, quit, goodbye].
logon - The process of connecting to a BBS. The is what occurs
after you have called the computer and the phone starts to ring,
but before you actually start using the BBS. "Logon" can also
include the process of entering your name and password (which is
also called sign-on). [See also signon].
long distance call - A telephone call that is outside your local
calling area, and that you must pay for. [See also local call].
lowercase - The letters that are normally used, such as in this
sentence. The other kind of letters are UPPERCASE. [See also
uppercase].
lurk - This is a term used on some CB simulators, which means
that the person is leaving his computer for a while (and there-
fore will not be able to respond to messages).
LZH - This file extension refers to an archive that was com-
pressed with the program LHARC. You need to get the program
LHARC from a BBS before you can un-archive the file. [See also
archive, unarchive, LHARC].
---M---
macro - A series of instructions or text that can be entered by
hitting a couple of keys. For example, a communication program
might let you enter your user name and password just by hitting
CTRL-N. [See also trigger character].
mainframe - A large computer that many people can use at the same
time. Usually, a mainframe computer is owned by a large company,
and it has a lot of memory and storage for its users. Some
mainframes have phone lines connected to them so that employees
(or other authorized people) can use the mainframe from home.
make/break pulse ratio - During pulse dialing, the make/break
pulse ratio is the ratio of the time that the phone is off the
hook to the time the phone is on the hook. In America and Cana-
da, it should be 39/61.
manual-syncing driver - This is what a BBS uses if the BBS pro-
gram can not determine directly what the user's bps rate is, and
the user must hit the return key several times before the BBS can
figure out the user's speed.
mark - When you are looking at the titles of messages to read,
some BBS programs will allow you to choose certain ones you want
to read. This is called marking.
mark bit - A bit that is set to 1. [See also space bit].
mark parity - This is when the parity bit is always set to a
binary 1. [See also parity bit, format].
maximum string length - In V.42bis data compression, this refers
to the maximum length of data (in characters) represented by one
word. It can range from 6 to 250 characters, although it is
usually 32.
menu - A list of options that you can choose from. A BBS might
have a menu that lets you choose from reading messages, download-
ing, or logging off. In reality, there would be many more op-
tions.
message - Any text that is left in a message base on a BBS.
These can range from questions for other users to answer, to
information on new computer programs, to just about any topic you
could imagine.
message base - A group of messages on a BBS pertaining to a
certain topic. For example, a BBS might have message bases for
general messages, computer-related messages, and social informa-
tion. Some BBS's have dozens or even hundreds of message bases.
[Same as subboard, board].
minicomputer - A scaled-down version of a mainframe. A minicom-
puter usually has many terminals connected to it, and can run
many programs at the same time. It is more powerful than a
microcomputer.
MNP - Microcom Networking Protocol. A type of error control and
data compression, created by Microcom, that many newer modems
use. It is built into the modem, unlike software error correc-
tion in file transfer protocols. There are different MNP levels.
Levels 1-4 are error control protocols, and level 5 is a data
compression protocol that can compress data to about 50% of its
original size. A modem with MNP-5 also has MNP-4. MNP 1-4 is
also included in the CCITT V.42 error correction system.
MNP direct mode - This is a mode used on modems with the MNP
protocols, where the speeds from the modem to the remote modem
and to the computer are the same. Also, there is no buffering,
and no flow control. [Same as direct mode]. [See also MNP
normal mode].
MNP normal mode - This is the more common mode used with modems
that have MNP capability, where the speed from the computer to
the modem can be higher than the connection between the modem and
the remote modem. This mode uses buffering to prevent lost data.
[Same as normal mode]. [See also MNP direct mode].
mode - The state that a computer or a program is in. For exam-
ple, a computer can be in a text mode, and a communications
program can be in a chat mode (which operates differently than
the normal mode).
modem - MODulator/DEModulator. This is a computer peripheral
which allows a computer to communicate over telephone lines.
This is the heart of computer telecommunications. The main
factor that differentiates modems is their speed, measured in
bps.
modem ready - See DSR.
modify - See edit.
modular cord - A standard telephone cord, with a modular plug at
either end. [Same as modular line. [See also modular jack,
modular plug].
modular jack - The square hole in which you put telephone cord
(that has a modular plug). [See also modular cord, modular plug,
42A block].
modular line - See modular cord.
modular plug - The square piece of plastic at the end of a tele-
phone cord. It plugs into a modular jack. [See also modular
cord, modular jack].
modulate - When a modem changes information from computer bits
into tones that can be transmitted over the phone lines. Differ-
ent methods of modulation are PSK, FSK, and FDM. [See also
demodulate, PSK, FSK, FDM].
modulation scheme - The method that a modem uses to modulate
data. [See also PSK, FSK, FDM].
MTA - Message Transfer Agent. This is what moves data across a
network under the X.400 electronic mail system. [See also
X.400].
multiple-speed - This refers to a modem that can operate at
several speeds. Most modems are capable of doing this. While a
modem may be listed as having a speed of 2400bps, it most likely
also can operate at 1200bps and 300bps.
multiple-state modulation - A modulation scheme that sends more
than one bit per baud.
multi-line BBS - A BBS that has more than one line or node. [See
also line].
---N---
NAK - This control character (CTRL-U) is sometimes used by commu-
nications or BBS programs (usually in file transfers) to indicate
that the information it received was bad. NAK stands for Nega-
tive AcKnowledgement. [See also ACK].
negotiation scheme - See feature negotiation.
network - A group of BBS's that are "linked" together. This
means that the BBS's share messages and sometimes files. Usually
the BBS's will call each other late at night to get the messages
and files. [See also echomail].
new user - When you use a BBS, usually you will have the status
of new user for the first few calls, until the SysOp verifies
your account (at which time you will normally be considered a
registered user). A new user usually has less privileges, such
as not being able to download programs.
news - Some BBS programs will have announcements that are shown
when you log on to the BBS. These are often referred to as news,
since they often inform you of changes to the BBS. [Same as
system news]. [See also sign-on message].
next - A command in BBS programs that will let you view the next
message in the message base.
node - See line.
noise - See line noise.
noise level - See noise power.
noise power - The "loudness" or strength of noise on a phone
line. It is measured in -dBm's. [See also signal power].
non-destructive backspace - This is when a communications program
will not delete any characters on the screen when the backspace
key is pressed. [See also destructive backspace].
non-volatile memory - This is memory that many modems have which
is not destroyed when the power is turned off. Using this memo-
ry, you can store a certain configuration in the memory, and have
the modem automatically use the configuration when you turn it
on.
normal mode - See MNP normal mode.
null character - The ASCII character 0, or CTRL-@. This charac-
ter usually will not be printed on the screen. It was originally
used when communications programs were slower and could not
receive information as fast as it was sent, so BBS programs would
send these characters after every line to slow down the speed at
which information had to be received.
null modem - A special connection between two computers that will
make the computers think that they are hooked up to a modem, so
that the two computers can communicate with each other.
numeric result codes - These are result codes that are printed as
numbers, rather than words. [See also result codes, verbal
result codes].
---O---
odd parity - This indicates that the parity bit is always set so
that the sum of the bits set to 1 in a byte, plus the parity bit,
is an odd number. [See also parity, format].
off hook - The state that your telephone is in when you pick it
up. In non-computer life, it usually means when the telephone
connection is accidentally disconnected, such as "Someone must
have left the phone off the hook." A modem that takes the phone
"off hook" is taking control of the phone line, and it will
usually then dial a phone number for you. When a telephone line
is "off hook," you are not able to receive calls from other
people, unless you have call waiting. [See also on hook].
off hook button - This is the button on a real telephone that is
depressed when you put down the receiver. It signals the phone
company when your phone is off hook, and ready to place calls.
off line - When your computer is not connected to another BBS.
[See also on line].
on hook - When your telephone is not being used, and it is ready
to ring if someone calls. [See also off hook].
on-line - When your computer is connected to a BBS. For example,
some communications programs will keep track of how long you have
been on line. This lets you know how long you have been connect-
ed to the BBS.
on-line conference - This is when a group of people "get togeth-
er" and have a conference using their computers. Some of the
major on-line services do this. [Same as real-time conference].
on-line games - Any game that is played on a BBS. Sometimes they
are played in real time against other players who are using the
BBS at the same time, and sometimes they are played by making a
move and waiting for their opponent(s) to make their move when
they next call. [See also Role Playing Game].
on-line information service - Any on-line service that provides
information. Most commercial systems fall into this category.
[See also on-line service].
on-line mode - See data mode.
on-line service - While this can refer to any computer that is
hooked up to the phone line, it usually means a pay service such
as Compuserve or GEnie. [Same as on-line system]. [See also
on-line information service].
on-line system - See on-line service.
originate - To call another computer and connect to it. The
originating computer is the one that placed the telephone call
(as opposed to the BBS, which is the answering computer).
originate-only modems - Some older modems only operate using an
originate frequency, which means that if you try calling one, you
must change your modem to send an answer tone. This can be done
on many modems by typing ATDT, the phone number you want to call,
and then the letter R (before hitting return).
originating computer - The computer which dials another computer.
This is most likely referring to your computer (unless you have a
BBS, or other people are calling your phone number, and you have
your computer's modem answer the phone). [See also answering
computer].
originate frequency - This is the frequency of the carrier that
is used by the modem that places a call to another modem. [See
also answer frequency].
originate mode - This is when a modem is ready to place a call,
rather than accept an incoming call. [See also answer mode].
---P---
packet - [1] A group of bits sent by a modem that comprise a byte
of information. [2] A group of bytes sent by a file transfer
protocol.
packet switching network - A telecommunications service that
transmits data from one computer to another using packets of
data. They usually have telephone numbers in most areas of the
country so that users can connect to on-line services without
toll charges.
pad - This happens when a file that is being transferred ends in
the middle of a block of data. The communications program must
add blank data to fill up the block. This is called padding.
[See also protocol].
PAD - Packet Assembler/Disassembler. This is a device that
disassembles incoming packets, and assembles outgoing packets.
page - [1] (noun) A page is one screen's worth of information.
Many BBS's will automatically wait for you to press a key after
it has sent you a page of information. [2] (verb) to alert the
SysOp that you would like to speak with him. Many BBS's will
allow you to do this, and it will make beeping sounds so that the
SysOp will know you want to talk to him. [Same as yell]. [See
also chat].
PAK - [1] The extension for files archived with the program of
the same name. You need the program PAK to un-arc an archive
with this extension. [2] The program itself. [See also archive,
unarchive].
parallel - This is when a computer sends data one byte (or any
number of bits other than one) at a time. This is faster than
the alternative, serial. [See also serial].
parallel interface - Any interface that transmits or receives
more than one bit at a time. In most cases, 8 bits are trans-
ferred at a time. The RS-232C standard involves a parallel
interface. [See also serial interface].
parity bit - Most modems have the capability to send an extra bit
for every byte sent, which is used to help sense errors. This is
called the parity bit. It can be set to no parity, mark parity,
space parity, odd parity or even parity. Most BBS's do not use a
parity bit. [See also format, mark, space, odd, even].
password - A special code that only you should know. This code
will allow you to gain access to your account on a computer.
Different BBS's have different rules as to how long your password
can be and what characters can be used. You should not use a
password that is easy to guess (such as your name, or
"password"), because a hacker might try to gain access to your
account by guessing your password.
pause - On most modems, you can send the modem a command that
will pause at some point while dialing a number. This can be
useful on PBX systems, if you have to wait for a dial tone.
PBX - Private Branch Exchange. This is the telephone system that
many offices have, allowing extensions for each telephone, and a
connection to the main telephone system.
PC-Pursuit - A pack | |
