>>>OK. Look in your manual for something along the lines of Voice Line Selection or something similar. You do have a voice capable modem there, right?
>>
>>I have a US Robotics Sporters 56.
>
>Well, as long as it say Fax/Data/Voice somewhere, you can do most anything with it. Now do you understand what I was saying about TAPI? It insulates you from a lot of this fiddling around...

Here is the quote from my Supra manual:

To initiate a call with the speakerphone, issue:
   AT#CLS=8
   AT#VRN=0
   AT#VLS=6 (Selects the speakerphone)

It is recommended to set the VRN command to 0 which disables ringback detection before reporting the VCON message.

   ATDT<number>
The modem then responds with:

   VCON (based on the AT#VRA and #VRN setting)

Additional DTMF (for example in a voice mail application) can be entered by issuing:

   AT#VTS=<digit>

When DTMF digits are sent, it is recommended that the default value of the tone length be changed to 100 ms using the
command #VBT:

   AT#VBT=1

The call can be transferred (PBX function) by entering the flash dial modifier (AT#VTS=!).
Terminate the call with:

ATH

the #VLS is the key here. 9 different settings for source of audio.