VOIP Tech Chat → voip.ms anti-telemarketer IVR - Greeting Message gets cut off

Hello Everyone,

I've implemented the classic anti-telemarkter IVR with VOIP.MS and a SPA3102 gateway. However, I noticed from time-to-time that the beginning of my message will be cut off.

I am not sure if it is the SPA3102 taking too long to bridge the voip call or if it is voip.ms taking too long to detect an answer. Anyone else have a similar issue?

Possibly, your router is sometimes translating the RTP source port number and VoIP.ms is recovering by comedia (sending RTP back to whatever address / port it's coming from). If you can capture traffic on the WAN side of the router you should be able to see it happening.

If that's your problem, you should be able to fix it by forwarding in your router, the UDP port range (from RTP Port Min to RTP Port Max) to the SPA3102. Also, make sure that no other VoIP device on your LAN uses ports in that range.Huh? I assume that the caller is calling a POTS line, which your SPA3102 is sending to an IVR at VoIP.ms. In that case, VoIP.ms is answering, not detecting an answer. OTOH, if the caller is calling a DID at VoIP.ms that's routed to an IVR, your SPA3102 is at that point not involved at all.

Yes my SPA is answering the call them immediately forwarding the call to voip.ms via a sip uri. Most of the time the message pays five but about 20 to 30 percent of the time the first few seconds are cut off. I think bbm it maybe voip.ms because this happens if I call my sip directly via a soft phone... anyone else have this problem?

Why do you have it answer first? My similar setup has (in PSTN-To-VoIP Gateway Setup) Off Hook While Calling VoIP set to no. Changing this is unlikely to fix your problem, but it will reduce the amount of silence heard by the caller until the IVR answers.I had suspected a network issue and that test, by itself, does little to refute the hypothesis (though it does show that an SPA issue is unlikely). Stronger claims would be:

"This happens if I call my SIP directly via a soft phone, even when my PC is connected directly to the modem in bridge mode and gets a public IP address."

or:

"This happens if I call my SIP directly via a soft phone at my friend's house. He has a different ISP and router."

You might also try temporarily forwarding to a free Callcentric account set to go straight to voicemail. This won't be a real IVR, but you can see whether the first few seconds of the greeting sometimes gets cut off.

Or, if you have some networking knowledge, you could try my favorite approach, which is to find out what is actually going wrong.

Thanks for the comments, I'll keep them in mind and monitor the situation. Today voip.ms seems to be acting better - but like I said it's not every time the message gets cut off :S