How can I make voice call/How can I identify call using AT commands in visual basic? I am attempting to call a modem using a local modem connected via USB. Programming language is VB.NET and I am using the SerialPort control to talk to the modem. to call and send a voice I try many times.
You start voice calls with AT command ATD12345678; and (circuit switched) data calls with ATD12345678 (for phone number 12345678).
If you have not worked with AT commands before, by all means read the V.250 specification (linked from https://stackoverflow.com/tags/at-command/info). It will teach you all you need to get started using AT commands correctly.