I need to find a basic rs232 voice modem for a proof of concept device. The final product will have the functionality built in but for now I need an external solution.
The application will generate DTMF codes, and send a voice message. The modem needs basic hayes commands, enough to go off hook and dial out, send a message and hang up or hold the line open. ARM9 processor running a uLinux distro.
Any help would be appreciated.
Joe
You don't need a modem, just normal POTS service and at most a relay to connect/disconnect. Then it is your choice between DTMF and pulse dialling.
This is possible with the ZyXEL U1496E(+) series of modems. However, you will need quite a bit of time to get it to work, and even then it wont be very reliable. I would recommend you to not use a modem at all, but rather a line-interface module (MITEL does some, IIRC MH44288 or so is a product code to look for). These convert the phone line into audio-in and audio-out, plus control lines to pickup/hangup. This line interface, an ADC/DAC and off you go. No Hayes, no char-pacing, no CELP, no stuck sessions, no nothing.
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