Chapter 6: Modem Guide
6-8 CSMIM-T1 Hardware Installation Guide
V.32 and V.32bis Protocols
The ITU-T V.32 protocol is for full-duplex data transfer over general
switched telephone networks at 9,600 and 4,800 bps. V.32 employs echo
cancellation and trellis coded modulation.
The ITU-T V.32bis specification enhances V.32 by adding 14,400, 12,000,
and 7,200 bps speeds and special rate sequences to shorten speed
upshifting and downshifting.
V.23 Protocol 1,200 Bps Half-Duplex Operation
The modem supports one V.23 mode - main channel half duplex at 1200
bps.V.23 half-duplex operation is available only for direct and normal
connections. For V.23 half-duplex connections, set %F3 on both
modems.
The features described in this manual apply to V.23 operation, except that
the modem does not support:
•V.54 digital and analog loopback.
•MNP and LAPM connections.
Table 6-2 Configuring the Modems for V.23 connections
When %F1, %F2, or %F3 is set for V.23 connections:
Protocol Command
V.23 (1200 bps half duplex) %F3
NOTES When you configure your modem for V.23 operation by setting
the %Fn command to a value other than 0, this disables other
modulation protocols.
When the modem establishes a V.23 half-duplex connection it
displays CONNECT V.23 HDX.
When the originate modem is set to normal mode, you must
send a few characters to the answer modem before the
originate modem can fall back to a V.23 half-duplex
connection.