If i will opt-out of the voice circuit, will the Arduino with GSM Shield still produce an audible ringtone to the called party? Yes or No?
* GSM shield
* Voice circuit.
With no voice circuit the call will send nor receive any sound
created Mar 2012
by Javier Zorzano"
The modem itself does not produce a ringtone, but it is possible via modem AOUT2 output. See the manual for more information M10 (Audio Interfaces section): http://arduino.cc/en/uploads/Main/Quectel_M10_datasheet.pdf