Yealink Forums

Hello All,

I have been doing some testing with Freeswitch 1.4.13 and noticed that I have not been getting audio on calls between Zoiper / CSipSimple and my Yealink T46G. After further investigation I narrowed the issue down to GSM.

Between Zoiper / CSIPSimple (with only GSM enabled) and Yealink T46G (with PCMU, PCMA, G722 enabled) calls work flawlessly in both directions.

Calling between the Yealink T46G (with only GSM enabled) and Zoiper / CSIPSimple (with only GSM enabled) there is no audio.

Calls between Yealink T46G (with only GSM enabled) and my Yealink T20 (with PCMU, PCMA, G722 enabled) the audio on the T20 end is garbled and no audio on the T46G.

Calls between Zoiper / CSipSimple (with only GSM enabled) and Yealink T20 (with PCMU, PCMA, G722 enabled) we have two-way audio both ways.

It would be great if someone can verify this GSM issue on the T46G, I have tested with the latest Firmware 28.72.0.45 as well as the previous 28.72.0.26.

I have come to the conclusion that GSM on the T46G might be broken so it would be great if someone is able to confirm if this is the case.

Thanks

Errol

Hi Errol,

I am sorry to tell you Yealink T46 phone would not support the GSM codec any more in the V73 version.
For your doubt, during the SDP negotiation, the initiator give some types of support codec , and in which the recipient to choose their own kind, and then complete the interaction. Followed by the establishment of the RTP stream. So if you set the other sides don't have same codec in the codec list and your pbx server does not support the transfer function of the codec, they can't establish call with each other.

So please enabled the same codec on other sides then try again.
For example, Calling between the Yealink T46G (with G722, PCMU,PCMA enabled) and Zoiper / CSIPSimple (G722, PCMU,PCMA enabled) to confirm whether there is audio issue?

BTW, may I know why do you need to test the GSM codec with Yealink phone?
thanks

(11-01-2014 01:37 PM)Yealink_Wilson Wrote: [ -> ]Hi Errol,

I am sorry to tell you Yealink T46 phone would not support the GSM codec any more in the V73 version.
For your doubt, during the SDP negotiation, the initiator give some types of support codec , and in which the recipient to choose their own kind, and then complete the interaction. Followed by the establishment of the RTP stream. So if you set the other sides don't have same codec in the codec list and your pbx server does not support the transfer function of the codec, they can't establish call with each other.

So please enabled the same codec on other sides then try again.
For example, Calling between the Yealink T46G (with G722, PCMU,PCMA enabled) and Zoiper / CSIPSimple (G722, PCMU,PCMA enabled) to confirm whether there is audio issue?

Hello Yealink_Wilson,

I think you misread or misunderstood my original post where I did also mentioned that I also tested Calling between the Yealink T46G (with only GSM enabled) and Zoiper / CSIPSimple (with only GSM enabled) there is no audio.

There is no issue when we use G722,PCMU,PCMA on both ends or even if the other end has GSM enabled and the T46G only has G722, PCMU,PCMA enabled because Freeswitch will do the transcoding.

Quote:BTW, may I know why do you need to test the GSM codec with Yealink phone?
thanks

The GSM codec is actually listed as one of the codecs in the T46 (Firmware 28.72.0.45) and it was in my enabled list so when ever a call came from a softphone that offered GSM both devices negotiated GSM but then I got no audio between the T46G and the softphone which lead me to believe there was a problem with GSM on the T46G.

So I merely wanted to confirm whether the GSM codec issue is a known issue so that we wouldn't enable it in the future.

Thanks

Errol

Hi Errol,

According to your scenario describes, it is possible a bug of T46. It need our R&D to do more troubleshootings then confirm it whether has bug using GSM codec. But in the V73 version, we have disable this codec and won't do support with it. So would you please upgrade the firmware to V73 beta2 to do your test? You can download the firmware from this announcement. And please reset the phone to factory after upgrading. Then the GSM codec will disappear in the codec list of T46.

V73 Beta2 Version Firmware And Release Notes of Version 73 Release

thanks