Universal Protocol Compatibility; Error Control - ZyXEL Communications COMET 336 User Manual

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%)
V.34bis 33,600/31,200
V.34 28 800 - 2 400
V.32bis 14 400
V.32bis 12 000
V.32bis 7 200
V.32 9 600
V.32 uncoded 9 600
V.32 4 800
V.29* 9 600
V.29* 7 200
V.29* 4 800
V.27bis* 4 800
V.27bis* 2 400
V.26bis* 2 400
V.23 1200 / 75
V.23 600 / 75
V.22bis†
V.22† 1 200
V.21 300
BELL 103 300
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.
24 Advanced Data Communications
Baud rate
(+/-0,01%)
2400
multiple
2 400
2 400
2 400
2 400
2 400
2 400
2 400
2 400
2 400
1 600
1 200
1 200
1200 / 75
600 / 75
2 400 600
600
300
300
Modulation Carrier Freq
[Hz]
TCM 1800
multiple multiple
128-TCM 1800
64-TCM 1800
16-TCM 1800
32-TCM 1800
16-QAM 1800
4-DPSK 1800
16-QAM 1700
8-QAM 1700
4-DPSK 1700
8-PSK 1800
4-DPSK 1800
4-DPSK 1800
FSK
FSK
16-QAM 1200 Orig.
2400 Ans.
4-DPSK 1200 Orig.
2400 Ans.
FSK
FSK