voice only heard in one direction

[j.butterfield]

I have a 2600 with a FXO port in it. I can dial into the port from the PSTN and get to an 7960 phone. The call gets established but the IP phone cannot hear the person calling on the FXO line, but the person on FXO line can hear the IP phone user. What's up with that? I suspect a codec issue, but I believe both the 2600 and CCM are using g711. Also the fxo line can dial extensions once voicemail picks up so some info is getting through, just not the voice.

Thanks in advance

[j.butterfield]

It appears that I can select ANY codec on the router EXCEPT g711u or g711a and it will work with varying degrees of quality. I still don't understand why I can't select the correct codec? Regardless of the codec I select the phone still says that both tx & rx are g7.11u (I get this by pressing the "I" button twice to see the stats. Any ideas?

Thanks

[j.butterfield]

Found the problem. I was using 12.2(1) and that seemed to be the major problem. I downgraded to 12.1(5)T8 and that is what fixed the problem. I can now use g711u on the router and it works.

Thanks for all the advice.