AT commands in modem INF file

Dear All,
what is the using of specifying AT commands in modem inf file for data, voice etc?
those AT commands will be allowed by modem.sys to send to lower filter modem driver, incase we are loading as filter driver?

xxxxx@gmail.com wrote:

what is the using of specifying AT commands in modem inf file for data, voice etc?
those AT commands will be allowed by modem.sys to send to lower filter modem driver, incase we are loading as filter driver?

The point is that not all modems implement the exact same AT command
set. If an application wants to answer a call, it needs to know what AT
command to send (or, at least, some API somewhere in the stack needs to
know). You find that out by looking up the registry entries placed
there by the INF file.


Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.

Tim Roberts wrote:

The point is that not all modems implement the exact
same AT command set. If an application wants to answer
a call, it needs to know what AT command to send (or, at
least, some API somewhere in the stack needs to know).
You find that out by looking up the registry entries placed
there by the INF file.

But despite all that, when your modem gets installed for the first time, it will always be issued “ATQ0V1E0”, no matter what (or at least it always did on XP). You can see this string hard-coded into modemui.dll. This causes a lengthy delay during device installation if you don’t answer it with “OK” (or maybe “ERROR”.)