I’m developing an audio interface to convert the 4 wires of Q2686 gsm module to 2 wire audio line to connect a standard telephone (standard GSM Gate).
I use standard telephone and connect his mic in and spk out to spk out and mic in Q26. But there are echo in remote mobile station. Why?
Can you hlep me with interfacing standard analog phone to GSM module Wavecom ?
I hope, that it´s standard aplication, but I dont find some app notes or schematic for this interface…