Solved Poor sound quality on snom dects

[JVM-tech]

Hello,


I have a 3 cx installation running on a windows10 pro pc with the latest 3cx versions. The customer did complain over poor sound quality in some calls. Never took much attention to it because i thought it was the other side (cell phone) that created the poor quality.


Installation:

PC with windows 10 pro

Latest version of 3cx
1 fix phone Snom 725 (latest firmware)
3 dect antennas SnomM700 (latest firmware)
4 snom wireless phones M65 (latest firmware)
1 Patton converts phone line to Sip

In the meanwhile the customer had more complaints so i asked to do some easy checks. This was the result.
- Call from a wired phone Snom 725 calling outside or receiving with perfect sound quality. So no problem here.
- Cals with the Snom dects (in and out) are creating the problems. More in detail the receiving voice on the snom M65 is verry clear. It is the external caller that is receiving bad sound. So bad that my 3cx customer had to repeat himself several times.

So in a nutshell:
- No problem with the wired phone = also no problem with the 3cx PABX and the outside that goes over a phoneline to voip converter (Patton)
- Only the dects have problems and this only in one way. All 5 M65 have the same issue




Anny ideas where to look

 

[AWS2P]

check audio codecs and align order everywhere in Trunk, extensions, Gateway , and global settings on PBX . once done reprovision phone to apply new order

 

[JVM-tech]

First Thanks for the quick responds. Are there prefered codex priority? Within a hour i can Check thee settings and will give feedback.

 

[Alphabetic]

Assuming dect phones are set up local?

Have you tried performing an echo test by dialling *777

 

[JVM-tech]

A took a look to the codex priority. All those are automatic generated by 3CX. Never changed those. Did also do a check with one of my other 3cx systems and i have the same settings there. Never the less. Here they are:

Dect: Snom M700
G711u
G711a
G722
G729

Fix: Snom 725
G711u
G711a
G722
G729

Portable: Snom M65
GSM-FR
G729
G.711 U-law
G.711 A-law
G722

Global 3CX local:
PCMU
PCMA
G722
GSM
G729
OPUS

Global 3CX external:
GSM
G729
G722
PCMU
PCMA
OPUS

No info about the gateway.

Any proposel with codex firts. Knowing the fix Snom is working OK

 

[AWS2P]

change order on M65 to
G711u
G711a
G722
G729

Global 3CX external:
G711u
G711a
G722
G729
GSM
OPUS

 

[JVM-tech]

Thanks Aws2P,

I wil do the change tomorrow after i contacted the customer.
I will give feedback of the result.

 

[JVM-tech]

Update,

I did changed the Codex priority like AWS2P proposed. First call to customer looks perfect. He will do some test first half of the week and give me feedback. Let us hope this will do the trick. Before the end of next week i will post a update to let you now the final result from the customer.

Thanks for the support.

 

[AWS2P]

Normally if prefered codec where you are is G711U and you set it everywhere in first you should be out of of audio transcode problems and avoid lose of quality.
Now while calls are external you don't know on the other end which codec is expected and you can do nothing

 

[JVM-tech]

Problem solved.
Just to inform. With a further search a found out that there was 1 M700 antenne down. This is a fiture that is not visible in the 3C portal only if i log in to the main M700 and look to his Multicell Chain. This could be a good future to get into the portal in a next release.

Thanks again for the support !!

 

[AWS2P]

Thanks having shared your findings