Glossary
FP Modem-EU Technical Manual
RS232C baud rate
Also called DTE speed; the transfer rate in bps at the serial interface between DTE and modem.
The RS232C baud rate may be higher than the line transmission speed because of the
compression capabilities of the modem.
RTS
Request To Send, Switch sender to ON, signal of the V.24 interface.
Serial
Normally there is only one data line available for data transmission. Data traffic takes place in a
serial manner, i.e. transmission is carried out bit by bit.
Synchronous
For synchronous transmission the connected units deliver frequency signals for controlling the
frequency of the data transmission. See also asynchronous.
T.4
Compression standard (ITU-T) for fax machines (G3).
T.30
Fax transmission protocol with error correction (ITU-T). Describes initialization of calls,
selection of the transmission mode, data transmission, confirmation of reception and
termination of calls.
TAE
Telephone jack. Socket system of Deutsche Telekom since 1989. In Germany only the 6-pin
version, TAE-6, is used. We distinguish between TAE-N for devices like modems, answering
machines or fax machines and TAE-F for telephones.
Tone dialing
See DTMF.
Transmission mode
Type of connection. Without error correction procedure: DIRECT mode, NORMAL mode. With
error correction procedure: RELIABLE mode.
V standards
ITU-T standards for data transmission.
V.17
Fax transmission standard (G3) for 14400 bps (2400 baud). Half duplex transmission results in
a 7200 bps transmission rate.
V.21
Modulation standard, bit rate 300 bps.
V.22
Modulation standard, bit rate 1200 bps.
V.22bis
Modulation standard, bit rate max. 2400 bps.
V.23
Modulation standard, bit rate 75/1200 bps half-duplex, i.e. the send channel possesses 1200
bps, the receive channel possesses only 75 bps. Important especially for T-Online (classic) or
Datex-J/Btx-switching exchange.
V.24
CCITT standard for serial data transmission. Defines the functional characteristics (e.g. pin
102
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