Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

cisco IP phone rings but no voice


I am working with SIPH323 protocol converter. I have cisco SIP phones in my SIP network and cisco SKinny phones (H323) with CallManager in H323 network.

When I call from SIP to Skinny phone, it rings and gets connected also. But I dont hear anything (voice/audio) in skinny phone what I speak from SIP phone.

Similarly when I call from Skinny to SIP phone, I dont hear the ringing tone of SIP phone in Skinny phone, but both phones get connected and I dont hear any voice.

I would appreciate if anyone could tell me the possible solutions for this problem.




Re: cisco IP phone rings but no voice

New Member

Re: cisco IP phone rings but no voice

This is probably a routing problem. A common problem with H.323 gateways is the source address. H.323 advertise a source address that the far end is to send the RTP stream to. However, this address is not neccessarily the address of the closest interface and can in fact be an address that the remote site cannot reach. And if that is the case, the only error is a lack of voice. Calls will still ring and connect, because that uses TCP, but the RTP stream will be lost in the ether.