User's Guide

The Operational View SB300 Series
Page 28 Proprietary and Confidential 2110059 Rev 1.0
The table below shows the fall back speeds from V.34 to V.22 as supported by the SB320 modem.
When ETC is enabled on the SB320 using the “super” AT command AT&F5 (described in the
CSC Operations section), the maximum speed of the modem is limited to the DTE speed (set at
19200 bps).
Protocols
Speed (bps)
V.34 19200 - 33600
V.32bis 14400 - 12000
V.32 9600 - 4800
V.22bis 2400
V22 1200 – 600
4.5.2.3. Configuration Issues
Using an SB320 in Wireline or CSC modes requires careful use of the AT commands that tune the
various elements controlling modem handshaking process. Optimizing for Wireline and CSC
modes requires different settings. Where one mode is improved with a particular profile or
settings, the other can be impaired by the same profile.
The specific sections on CSC and Wireline Operations (Chapters 6 and 7 respectively) give a
description of some of the key AT commands and S-registers associated with performance so that
the user can modify the modem configuration from its default settings if necessary.