Poor Quality on SIP Trunks

[Wendelspanswick]

Hi All

We have a 3CX V14 install with Yealink T23g handsets that uses a combination of ISDN30 trunks via a Patton gateway and SIP trunks via a TalkTalk ADSL line. The customer is happy with the ISDN30 but every time we put them on the SIP trunks we get complaints of poor speech quality.
The ADSL supports 7 MBs down and 0.64 MBs up so in theory it should support 10 simultaneous calls on the G.711 a CODEC although in practice we have never tried running more than 4 simultaneous calls.
We have monitored the router and it never approaches maximum bandwidth, the connection tests OK with no dropped packets, we are running out of ideas now, any suggestions.

 

[Wendelspanswick]

Think I may have answered my own question, SIP trunks were set to G.711 a and G.729 CODECs but Yealink handsets don't have the G.711 a in the config so I guess the calls were defaulting to G.729. Now I've changed the SIP to G.722 which the Yealinks do have in their config and I will run some tests.

 

[JasonNadeau]

Pcma and pcmu in yealink is g711a/u... with less than 1mb up personally I wouldn't attempt external voip (although that was my home setup for many years and it worked fine once I had qos setup.)

 

[Wendelspanswick]

Just to complicate things TalkTalk don't support G.722, only G.711a or u so it looks like we will have to modify the provisioning template for the Yealinks to add G.711.

 

[Wendelspanswick]

Pcma and pcmu in yealink is g711a/u... with less than 1mb up personally I wouldn't attempt external voip (although that was my home setup for many years and it worked fine once I had qos setup.)

That's interesting, I wondered why there was no G.711 on the Yealink, doesn't solve my problem though.