SYN

Sync character. Establishes synchronism and fills time in the absence of any data or control

 

character to maintain synchronism.

Synchronous

Data accepted or provided with an accompanying time signal.

Synchronous Data

An algorithm that allows the modem to run at a DTE rate higher than the DCE rate. This is

compression (SDC)

accomplished by receiving frames of data at the originating end, compressing, and then

 

transmitting the data at the slower DCE rate, and decompressing the data at the receiving

 

side. The compression algorithm is derived from the V.42bis data compression algorithm.

 

SDC only applies when synchronous data is framed in HDLC-SDLC-like format.

Tail circuit

A point-to-point, second-tier circuit directly connected (back to back) to the remote modem

 

of the first-tier circuit. The connection is made using a DCE/DTE crossover cable.

Training

A technique that adjusts modems to current telephone line conditions. The transmitting

 

modem sends a special training sequence to the receiving modem, which makes necessary

 

adjustments for line conditions.

Transmission rate

Bits per second passing over the telephone line or other communications circuitry.

Two-wire

A circuit consisting of one pair of wires.

V.22bis

See ITU V.22bis.

V.24

See ITU V.24.

V.25bis

See ITU V.25bis.

V.32

See ITU V.32.

V.32bis

See ITU V.32bis.

V.34

See ITU-TS V.34.

V.42

See ITU V.42.

V.42bis

See ITU V.42bis.

Glossary

6-Glossary

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