We used to have cisco ATA 186 for Fax machines with Pass through mode which worked fine with both inbound and outbound mode. Wherein we had configured audio mode parameters on ATA 186.
But now using ATA 187 for the same place and same config. Only out bound Fax to PSTN is happening while inbound call gets established but drops after about 5-10 seconds.
We are having H.323/225 trunks with service provider using codec g.729 for Voice calls but g.711ulaw pass through for fax calls. There is no problem with Cisco ATA 186 on same platform but 187 is not working fro inbound calls.
We are using CUCM v8.0.3.
Since 186 is no more avilabale we have to use 187
I would really like to know how we can solve this.
As I mentioned in my post we have H.225 trunk from service provider. We do not have any gateway in our DC. All PSTN voice reaches to us over MPLS from Service provider gateways.
We do not have access to any gateway config. how ever I have log files received from Servcie provider. I can post them if you want..
could you post your Trunk-Configuration (Screenshots)? Also you can send it via PM.
I have the same problem this weekend with a back2back sip trunk. We disabled the MTP on the Trunk and then inbound fax works.
Also if you use a CUBE (i know you use H225) with greater version 15 you must add the IPs of the endpoints to the CUBE trustlist.
i've remarked a particular behaviour on the ATA 187. when it has already established a logical media channel negotiated with g.711alaw the ATA sends a SIP/SDP invite to change the media for g.711ulaw, which make the channel to breakdown as we don't do media renegotiation. so i guess it's a ATA 187 bug, it was not supposed to send a SIP/SDP invite when RTP is already opened.
even this happens it's supposed to work with g.711ulaw with your network was designed for g.711u.
hope it helps something