USB Modem Voice Calls

Started by fhammer, June 05, 2014, 04:05:14 PM

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fhammer

I have a USB modem connected to a standard (POTS - Plain Old Telephone System) analog voice phone line. I'm using the Serial Extender to initialte voice calls. This works fine, up to a point.

I can initiate voice calls with no problem.

I can hear the dial tone, the call being tone-dialed, and the answering party's voice. The modem does not have a speaker, so I know that the tones and answerer's voice that I hear, are a result of the "incoming" analog signal being somehow routed to my computer's speaker. I can adjust the volume by simply using my computer's volume controls.

However, I haven't been able to find a way to talk to the answering party, through my computer's microphone. The answering party hears nothing. I have a standard phone attached to the same POTS line. I can always pick up the reciever and talk to the answering party. However, it would sure be nice if I could just talk through my computer's mike.

Does anyone know how to accomplish this?

Thank you.

....IFICantBYTE

Obviously your USB modem is working pretty well as a traditional "serial" device and it is also able to be driven by the AT commands set.

I don't know much about the old TAPI stuff, but I am amazed that it is routing the digitised "analog" audio through your sound card.. looks like it has set itself up as a proper old fashioned voice modem.
If it has, then from memory, you either need it to have a physical "mic in" jack on the modem (very unlikely on a USB modem), OR it has to behave like an audio device that you can control and "play" or stream audio (usually PCM wave) through so that the other party hears it.

This is old tech that as far as I remember, used to be handled by drivers that came with a voice modem and a software phone application (usually bundled as a voicemail/fax system).
I haven't seen anything like that since Windows 95 days.. and like I said, I don't know how you would do the next step for sure..... perhaps see if you have an audio device (other than your PC's sound card)registered in your devices (control panel) and if you do, then you might be able to somehow redirect your mic's audio to it using the TAPI or some Audio API and dll calls???

Hope some of this rambling helps.
Regards,
....IFICantBYTE

Nothing sucks more than that moment during an argument when you realize you're wrong. :)

fhammer

Thanks for the reply and the good ideas. I'll report back if I get something working, or give up.

Deana

....IFICantBYTE,.
Thanks for responding to this thread. Honestly I wouldn't have known where to start on this problem. Thanks for the input.
Deana F.
Technical Support
Wilson WindowWare Inc.

kdmoyers

Quote from: Deana on June 06, 2014, 09:32:57 AMHonestly I wouldn't have known where to start on this problem. Thanks for the input.
When discussing modems, it helps to be "of a certain age." (big grin)
I fondly remember the astonishing speed of my first 300 baud modem. It seemed the future had arrived.

-Kirby
The mind is everything; What you think, you become.

Deana

Kirby,
A lady never reveals her age... that is, unless she unintentionally reveals it due to lack of arcane technical knowledge.
;D
Deana F.
Technical Support
Wilson WindowWare Inc.

....IFICantBYTE

I am "only" 44, but, like Kirby, I do remember saving up and getting a 300/75 baud modem called a "Viatel adapter" for my Commodore 64 back in about '86 and thought it was pretty cool and fast at the time... it seemed so technically sophisticated because it didn't need an acoustic coupler (remember those?).. but in reality it was so slow! You could see the text being drawn to screen as it was received, with 8x8 colour squares and symbolic characters for graphics in between! - No web back then of course, just had a couple of phone numbers to dial into compatible BBS's.
A few years later, I got myself a state of the art 14400 on my Amiga... it flew compared to other modems I had used before and eventually was on the real web... Ahhh those were the days!

Regards,
....IFICantBYTE

Nothing sucks more than that moment during an argument when you realize you're wrong. :)

fhammer

Thanks for all the suggestions everyone.

For now I've given up on this one. I suspect that, since modems weren't intended for voice, they don't provide much voice functionality. The only reason they provide audible dial-tones, touch-tones, and incoming voice, is due to legacy use for identifying connect progress, misdialed calls, etc. The phone company needed to provide these features in order to make money selling external modems and POTS circuits for data. Later, the cheap USB modem developers, needed to preserve this functionality. Since cheap modems don't have speakers, they needed to route the analog input to the computers speaker. Generic USB modem drivers appear to do this.

Cheers.