COMSPHERE 3825Plus Modem
Glossary-2
November 1996
3825-A2-GB30-20
automode
To change modulations or rates within a modulation when modems first connect. A modem may
automode to a different modulation than what it is configured for due to the limitations of the
remote modem, or automode to a lower rate due to unfavorable VF line conditions during
connection.
autorate
To adjust to varying VF line conditions by changing the data rate to a higher or lower rate after
connection. The lowest rate the modem autorates to is 4800 bps; the highest possible rate depends
on the modulation the modems connected with. In V.34, the modems may autorate
asymmetrically.
baud
A unit of signaling speed that is equal to the number of symbols per second. This is not
necessarily the same as bits per second, although the terms are frequently interchanged.
Bisync
Binary Synchronous Communications. An IBM communications protocol that has become an
industry standard. It uses a defined set of control characters and control character sequences for
synchronized transmission of binary-coded data between stations in a data communications
system.
bit
A contraction of binary digit. A bit, which is the smallest unit of information, represents a one or
a zero (sometimes called mark or space).
bps
Bits per second. Indicates the speed at which bits are transmitted across a data connection.
buffer
A storage device used to compensate for differences in the data flow rate when transmitting data
from one device to another.
byte
A sequence of successive bits (usually eight) handled as a unit in data transmission.
CCITT
An advisory committee (Consultative Committee on International Telephone and Telegraph)
established by the United Nations to recommend communications standards and policies. Now
called ITU-T.
character
A letter, figure, number, punctuation, or other symbols.
character echo
A way to check the accuracy of data transmission by sending (displaying) all the characters being
transmitted to the monitor.
Class 1 fax
A fax modem standard. Under Class 1 computer software handles most of the protocol,
compression, and conversion tasks.
Class 2 fax
A fax modem standard. Under Class 2 the modem handles most of the protocol, compression, and
conversion tasks as well as modulation, leaving the computer free for other work.
command line
Contains the command(s) instructing the modem to perform a function. Command lines begin
with the AT prefix (unless disabled), and are executed when you press the Return key.
Command mode
One of two general modem operating modes. When in Command mode, the modem accepts
commands instead of transmitting or receiving data.
configuration option
Modem software that sets specific operating parameters for the modem. Sometimes referred to as
straps.
connector
An outlet on equipment and cables that provides a connection.
CSA
Canadian Standards Association.
CTS
Clear to Send. A signal indicating that the modem is ready for the DTE to transmit data.
