Inconsistant issue with incomming calls - ONE WAY AUDIO!

Basicly I have been unable to figure out whats going on as there are NO errors appearing in asterisk or on my PRI.

It is very inconsistant, and very confusing. This problem may happen 5-10 times a day.

Here is what is happening a call comes in, the main office picks up the phone - the person on the far end can hear everything, we can not hear them. we hang up, they call back, or we call them back and all is well.

There are no errors on the asterisk side - we are using a Polycom 601ip phone.

Has anyone seen this before? :question:

This type of thing happens to me fairly often when using a Radio Shack / VoipVoice CyberPhone connected to my laptop running XLite 3.0.

It’s usually on the first call after I boot up my laptop. I can hear the other end on the CyberPhone, but the other end can’t hear me.

If I hang up and call back it seems to work OK from then on until I power down the computer.

I have no ideas yet about what’s causing it.

we have exactly the same issue with the same phones ie Polycom ip600.

If anyone has a solution it would be much appreciated.

I have seen this problem before, and the only thing we put it down to was a CoDec mis-match, yeah i know what your thinking, but hey it is worth the shot having you look at it.

Check in your configuration files SIP or H.323 or IAX what ever your using and look at the allowed CoDec’s, then see which ones the Polycom one support, if it is over a local Network then i suggest you lock the Polycom phone in on the uLAW or aLAW CoDec and then set your Configuration file to only except this CoDec when making or receiving calls.

keep this in mind, receiving calls from the PSTN side will be either in aLAW or ulAW format, when it comes in Asterisk will have to Trans code it back to the CoDec your phone is using, this can cause one-way-audio and i have seen it happen a lot, restricting it to either of the LAW formats generally removes this problem, i would only recommend you use other CoDec is your phone does not support them the LAW form CoDec’s and some other lower rate CoDec.

However if you are Using these CoDec’s already, then i am not entirely sure what could be causing this problem, more information might be needed. Oh i should mention that Asterisk will not throw up an error on the CLI if there is a CoDec mis-match well not all the time.

What is a good test is too run the command 'sip show peers/friends" on the CLI and have a look at see what ports the Phone is using, what CoDec it is using versus the CoDec the TDM line is using, and then work it from there, sometime it is just the small things that can cause the major headaches :wink: