Why does the Vmail sample app drop the first 1-2 seconds of recorded speech using my voice modem?
Unlike more sophisticated telephony devices such as the MediaPhonics PhoneRider and Dialogic cards, modems really only have one audio channel and therefore can not record and play at the same time. If a wave file is currently playing it must first be stopped before recording can begin. In the case of the VMail sample application we are playing a wave file to tell the caller to “Press any key to record…..” When the caller presses a digit on the keypad, the event handler routine “TForm1.etTAPI1DigitReceived” is called. If the wave file is playing it must first be stopped before recording can begin. Additionally in this program we play a Ding wave file. For voice modems this should be commented out. If you comment out the code to play the Ding file and wait for the “Press any key to record…..” wave file to play completely before pressing a number, you will see that the first 1-2 seconds of speech recording is no longer dropped.
