Cabletron Systems CSMIM-T1 manual V.32bis Protocols

Chapter 6: Modem 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.

6-8 CSMIM-T1 Hardware Installation Guide