WARNING!
AT&T is not the modem test command but firm name.
AT&T is well-known on the modem market as chipset supplier. It has some extensions for the common command and S-register set which are shortly described below. Examples of AT&T chipset usage - Hayes Optima, IDC modems, etc. The short guide for AT&T voice commands is placed at WWW.NeuHaus.DE under the Link "Download / Handbacher / CYBERMOD Referenz" (thanks for Martin Mocker for this reference).
AT-commands and S-registers specific for AT&T
chipset are:
B - extended range of values which define connection speed and/or
protocols. This is implemented only in some modems, not at all.
N - automode option.
W - responses form.
&B - retrain control.
&Q - communication mode and data format. This command is the
extension and replacement of common &M command, but be careful!
It acts very different ways on several modems.
&U - Trellis encoding option (0 - enable).
&Y - power-on default profile to load.
S30 - inactivity timeout (similar to the \T command).
S37 - set the maximum connection speed.
Modem index
Author of this warp