ZyXEL Communications COMET 336, User Manual

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24 Advanced Data Communications
Universal Protocol Compatibility
Universal compatibility covers a broad range of ITU-T and BELL standards, and
provides data compression.
Various operation modes that can be achieved are as follows:
Standard BPS rate
(+/-0,01%) Baud rate
(+/-0,01%) Modulation Carrier Freq
[Hz]
V.34bis 33,600/31,200 2400 TCM 1800
V.34 28 800 - 2 400 multiple multiple multiple
V.32bis 14 400 2 400 128-TCM 1800
V.32bis 12 000 2 400 64-TCM 1800
V.32bis 7 200 2 400 16-TCM 1800
V.32 9 600 2 400 32-TCM 1800
V.32 uncoded 9 600 2 400 16-QAM 1800
V.32 4 800 2 400 4-DPSK 1800
V.29* 9 600 2 400 16-QAM 1700
V.29* 7 200 2 400 8-QAM 1700
V.29* 4 800 2 400 4-DPSK 1700
V.27bis* 4 800 1 600 8-PSK 1800
V.27bis* 2 400 1 200 4-DPSK 1800
V.26bis* 2 400 1 200 4-DPSK 1800
V.23 1200 / 75 1200 / 75 FSK
V.23 600 / 75 600 / 75 FSK
V.22bis† 2 400 600 16-QAM 1200 Orig.
2400 Ans.
V.22† 1 200 600 4-DPSK 1200 Orig.
2400 Ans.
V.21 300 300 FSK
BELL 103 300 300 FSK
G3 FAX Implemented according to T.30, V.17,V.29 and V.27ter.
Error Control
Error control keeps the modem data link error-free by detecting and re-transmitting
erroneous data. ZyXEL modems support both MNP and V.42 error control protocols.
The MNP protocol was an industry de facto standard developed and licensed by
Microcom, Inc. ZyXEL modems support level 4 and 3 error control protocols,
commonly denoted as MNP4 and MNP3. V.42 is a standard developed by ITU-T. V.42
supports both LAPM (Link Access Procedure for Modem) and MNP4. A V.42
handshake will try an LAPM connection first, and if not successful, it will try MNP4.
The error control (MNP4, LAPM) methods in modem to modem connections are based
on techniques utilized by both modems. They are explained below.