I'm experimenting with asterisk IP PBX. I have plugged in an old ISDN modem card, and used it to interconnect through an S0 channel with an existing ISDN line. That worked (in both directions).
Now I wanted to interconnect with our existing PBX (telrad) through one of it's S0 channels (client site, don't know if that makes a difference).
I can dial from the existing PBX to an asterisk extention, communication works fine. But if I try the oposite, dialing from asterisk to existing PBX, the phone rings (the phone on the existing pbx), the user picks his phone up but asterisks doesn't see that, instead I get a busy message in asterisk. ( Dialing out from asterisk through telrax PBX to external numbers works fine
anybody an idea?
thx in advance Arne