We have an Asterisk system directly connected to an Alcatel PBX. Our Asterisk system is using Digium TDM2400P card with FXS interface, while the Alcatel PBX is configured as FXO interface. Calls can be sent from Alcatel PBX to the Asterisk system perfectly. However, when we try to send calls from Asterisk to the Alcatel PBX, the Alcatel only answer the call occasionally. We tried to connect the FXS port to a telephone and the phone is ringing ok. We also tried to connect the FXS port to another FXO port from the same TDM2400P card, and the FXO port is also receiving the call perfectly. We tried to connect a CO line to the Alcatel and the Alcatel can answer the call with no problem!!
So, it looks like the problem is related to the interface between Asterisk and Alcatel. We tried to change the txgain settings in zapata.conf and turn on the boostringer option as well, but the problem persists. Does anybody have any clues on what the problem might be?
Thanks a lot.