| Duplex mismatch will not really cause 1 way speech. There will however be a severe degredation of packet flow which will cause all sorts of other problems due to packet collisions.
There is a signalling path and a voice path on the phone. The signaling path goes to the CS1000 (signaling server) and the RTP or voice path goes directly to the other IP endpoint (in this case the VGMC Card).
NAT can cause this problem (the IP trafic can find it's way in only 1 direction), or a CODEC mismatch. Check your zones for all devices.
In any case, you most likely have a Layer 2 issue in the data setup someplace. |