Zoom USB Faxmodem - Manual (Page 21)

Troubleshooting 19
To force different communication speeds
(protocols) Type these AT commands
and press Enter
Dualmode (V.90 or V.92)—56000 bps AT+MS=V92,1
V92 only (disable V.90)—56000 bps AT+MS=V92,0
V.90 only (disable V.92)—56000 bps AT+MS=V90,0
Disable both 56K and autorate on V.34—33600 bps AT+MS=V34,1
V.34—33600 bps AT+MS=V34,0
V.32bis—14400 bps AT+MS=V32B,0
V.32—9600 bps AT+MS=V32,0
2400 bps AT+MS=V22B,0
1200 bps AT+MS=V22,0
Notes: Some software allows these commands to be added to the
list of dial prefixes or the initialization string.
When the protocol is forced, the modem will not attempt to
connect at other protocols if it cannot connect at the forced
protocol. It will try to connect at the fastest speed available
within the forced protocol.
There are other configurations that can be forced as well. If you need
to select a particular configuration, use the AT command strings
shown below.
Remember that if you do this, the modem will not have received the
commands in your software’s initialization string as it normally would.
Using the ATZ command overcomes this problem if you have saved
all of your setup parameters in nonvolatile memory. (To save setup
parameters in nonvolatile memory in terminal mode: Type AT, fol-
lowed by the parameter settings you desire, followed by &W, and
press Enter. For example, if you type AT &C1 &D2 &W and press
Enter, the &C1 and &D2 parameter settings are stored.)