Zypcom Z34-PC, User Manual

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Data Mode
In data mode, the modem can operate at a line speed of
up to 56,000 bps. These modems will automatically
downshift during the initial handshake to communicate
with lower-speed modems. The C-Series modems
support the following modem standards:
ITU-T: V.34+, V.34, V.32bis, V.32, V.22bis, V.22,
V.21
USR: x2 56Kbps technology
Bell: 212A, 103
The C-Series modems implement a Hayes compatible AT
command set in data mode. This command set is
compatible with any communication application
software that supports the standard AT command set.
The AT commands for data are listed in Table 3-1 in
Chapter 3.
Error Control Modes
In data mode, the modem supports error correction
(V.42, MNP 2, MNP 3 and MNP 4) and data compression
(V.42bis and MNP 5). Error correction ensures error-
free data transfer, while data compression increases the
modem data throughput over the basic line speed of the
connection. Depending on the data stream, MNP 5 may
provide up to 2-to-1 compression. Alternately, V.42bis
may provide up to 4-to-1 compression. In V.34
modems, if possible, you should type \N4 to force your
software to hang up the call if an error control
connection is not negotiated during handshake. A
description of the AT commands that support error
correction and data compression is provided in Chapter
3.