We are having issue with MTA that when a VoIP call established, there was no upstream voice at the very beginning of the call. We are using Arris 502 and 602 EMTA, and Terayon BW3200 CMTS. The upstream modulation is 16QAM. We have tried to enable DSX QoS in modem config file, but there were about 100 out of 320 MTA could not get online with the config file with DSX QoS enabled. MTA went offline immediately after received the modem config file. Those MTA were across all upstreams. Each time, the modem received the log as follows,
02-22-2010 5:27:51 Registration RSP rejected unspecified reason
02-22-2010 5:27:51 UCD invalid or channel unusable
What may cause a VoIP call having issue of no upstream?
What may cause the MTA not able to get online with the DSX QoS enable?
Is there service flow limitation on the upstream of Teryaon CMTS?
Thanks!