95
machines today are Group 3, as are SupraFAXModems. Many older fax machines do not
support Group 3 faxing -- these machines typically won’t be able to send to a Group 3 machine
(or modem).
Half Duplex
Transmission allowing communication in only one direction at a time.
Hardware Handshaking (RTS/CTS)
A method of flow control used between the modem and the computer in which it is installed.
When ready to send data, the computer will send a Request to Send (RTS) signal, to which the
modem will reply with a Clear to Send (CTS) signal when it is ready to receive. CTS/RTS
prevents the computer from sending more data than the modem can handle.
Initialization
In modems, the establishment of an active configuration that, in whole or in part, supersedes
the factory configuration. By using an initialization string, you can configure the modem to
work well with your communications program. See
initialization string
.
Initialization string
(Also referred to as init. string.) In modems, a group of AT commands issued to the modem by
a communications program at the beginning of a communication session, that establishes an
active configuration. Initialization strings enable communications programs to work
smoothly with a variety of modems, and often you can choose an initialization string
appropriate for your modem from a list provided in your communications program.
See
initialization.
Interrupt Request (IRQ)
Signal used by a device, such as a mouse, to inform the CPU that it is present and functioning.
Internet Service Provider (ISP)
A company that provides end users access to the Internet.
ITU (also ITU-T)
International Telecommunications Union (also known as ITU-T, International
Telecommunications Union -Telecommunications section). An organization sponsored by the
United Nations that sets standards for communications technology. In computers, ITU
standards, such as the widely used V.32bis protocol that governs some high speed modem
communications, enable modems from different manufacturers to communicate with one
another. The ITU is the successor of the Comite Consultatif International Telephonique et
Telegraphique (CCIT).
ITU V.42
The international standard protocols for error correction (MNP 2-4 and LAPM).
ITU V.42bis
The international standard protocols for error correction (MNP 2-4 and LAPM) and 4:1 data
compression (BTLZ).
