Solved: Small Business Pro Phones 500 Series Problem

Velin Tsekov · ‎04-02-2010

Hi guys,

I decided to take a look the new Cisco Small Business Pro IP Phones 500 Series and to make a couple of tests. In my case the phones are SPA502G and SPA508G. I connected them behind UC520, with SIP Trunk connection with the provider. Configured dial-peer for the SIP trunk and set g711alaw as codec that I want to use. When I dial someone outside from one of these phones the voice quality is awful.I tried to change the codecs and so on. The only solution that I could found is in ephone configuration to set codec g729r8 dspfarm-assistant to make transcoding. After that when I made the call the quality for the voice is very good. These phones use spa5x5-7-4-3.bin firmware version.

I did a comparison and made a call from 7941 IP Phone without any additional configuration, and believe me the quality of voice is crystal.

Any tips? Is it possible to observe this problem because of firmware? Is there a new version?

BR!

Marcos Hernandez · ‎04-09-2010

Like I suspected, the SIP trunk seems to be doing G711alaw. The SPA500 phone should be able to negotiate it without issue, so maybe we have a bug. Can you ask your provider to do ulaw instead? I think this will help, but it is just a guess for now.

On my side, I will do some research to see if we are aware of issues with ALAW.

Marcos

View solution in original post

Marcos Hernandez · ‎04-08-2010

Can we take a look at the "show call active voice brief" for an active call made from a SPA phone?

Marcos

Velin Tsekov · ‎04-08-2010

Attached you can find the output.

Marcos Hernandez · ‎04-09-2010

Like I suspected, the SIP trunk seems to be doing G711alaw. The SPA500 phone should be able to negotiate it without issue, so maybe we have a bug. Can you ask your provider to do ulaw instead? I think this will help, but it is just a guess for now.

On my side, I will do some research to see if we are aware of issues with ALAW.

Marcos

Velin Tsekov · ‎04-09-2010

Unfortunately the provider can not do ulaw :(. I tried something else, namely ulaw with 7900 Series IP Phone to SPA Phone..there is no problem.

Please, keep me informed if there is any progress with this case.

Thank you in advance !

Cheers,

Velin

Marcos Hernandez · ‎04-13-2010

Velin,

You are not the only person reporting audio quality issues on these phones. Can you please open a support case so we can formally track this?

Thanks,

Marcos

Velin Tsekov · ‎04-13-2010

Hi Marcos,

You mean to open a TAC case, am I right ?

I will open one.

Thank you very much for your help.

Cheers,

Velin

Steven DiStefano · ‎04-14-2010

If its a UC520 and you have Smartnet, it can start with TAC, but since the phones are Small Business PRO, the case may end up with Small Business Support Center (SBSC) if you have the SB Pro Service ($19 for 3 years) on the phones. If its a UC540/UC560 with a SB Pro service contract, call SBSC straight away.

In any event, please tell the TAC Engineer taking your call that Nelson Seto and Steve Wang in the Cisco BU are looking at this issue. Have them contact me (Steve DiStefano) as well if they have questions. I raised your thread to them yesterday and they agreed to lab it up and confirm what you are seeing, so the TAC/SBSC person doesnt have to start all over trying to sniff down the folks to look at this.

Thanks and sorry for any problems this casues.

Velin Tsekov · ‎04-17-2010

Hi guys,

Thanks you a lot for the information. I will keep you informed about this case.

Best Regards,

Velin