I'm having trouble with a TDM400P card configured with one fxo and one fxs device. The system is a Mac G3 B/W running YellowDog 3.01 (2.4.22-2f kernel). The card is installed with a power cable, it configures itself properly at boot time, ztcfg and zttool shows everything is fine. Asterisk 1-0-28 starts fine with no errors and can sense a telephone handset going on and off hook on the fxs port. The simple switch starts up and stops when the handset goes back on-hook. The phone will also ring when a call is placed to it. On the fxo port it can sense an incoming call from the analog phone line, answer the call and detect hangup. However, neither the phone or the incoming call can receive or transmit anything. There's no dialtone when the phone is picked up, digit press are ignored and there is no sound heard on the incoming phone line when Asterisk playsback a sound file and cannot sense digit presses. ztmonitor shows that the fxs channel sends dialtone to the phone goes off-hook but nothing is received when a key is pressed on the phone. I've played with txgain and rxgain without any benefit. Anyone have any idea why ztmonitor would show that sound is being transmitted but yet there would still be no dialtone? Thanks, Stephen