In the following table, “protocol” means error correction and data compression. Note that the first two lines in the table are likely to be the most valuable.
Note 1: In the command strings shown in the table that follows, the character 0 is zero, not the letter “O.”
To force the different communication speeds | Type these commands and |
| press Enter |
Negotiate speed and protocol | AT &F |
(default setting) |
|
Negotiate speed only, no protocol (not recom- | AT \N0 |
mended) |
|
To force protocol | AT \N3 |
To force the different communication speeds | Type these commands and |
(i.e., maximum possible speed; actual speed | press Enter |
depends on line conditions and other factors) |
|
Connect at 56000 bps (V.90) | AT +MS=V90,0 |
Connect at 56000 bps (K56flex) | AT +MS=K56,0 |
Connect at 33600 bps (V.34) | AT +MS=V34 |
Connect at 14400 bps (V.32bis) | AT +MS=V32B |
Connect at 9600 bps (V.32) | AT +MS=V32 |
Note 2: You may find it helpful to include S95=44 in your initialization string. This enables the responses CARRIER (telephone line speed) and PROTOCOL, as well as CONNECT
Note 3: Some software allows these commands to be added to the list of dial prefixes.
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. You can always return to the modem’s default configuration by typing AT &F and pressing the Enter key. Remember that if you do this, the modem will not have received the commands in your soft- ware’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 AT termi- nal mode: Type AT, followed by the parameter settings you choose, followed by &W, and press Enter. For example, if you type AT &C1 &D2 &W and press Enter, the &C1 and
Chapter 4 Problems and Solutions | 25 |
