Garbled Audio

[emil]

I have a UC320W that gets garbled calls on the incoming mostly but outgoing ocasionally.  I have run the impedance matching and as well as adujsted the gain on the lines (due to low volume).  I have also had the telco test the lines.  I have not been able to fix the problem. I am out of ideas.

thank you in advance.

[Christopher Edgeworth]

Hi,

Make sure when adjusting the gain settings on the FXO, that the volume level on the SPA phone is set to the mid volume level.  We have seen problems were people have set the volume level to maximum on the SPA phone to compensate for low volume from the telco and this introduced distortion in the audio. 

Please open a case with the Cisco Small Business Support Center.  There are some advanced tools that they can run to analyze the audio and do some fine tuning.  It is best if you are on the customer site when you call.

Regards,

Chris

[emil]

The only issue is that the grabled calls are random.

[Christopher Edgeworth]

Hi,

Can you be a little more specific in what garbled means to you?

• are you hearing echo or sound like you are in a tin can?
• are you hearing choppiness like certain syllables are getting cut out?
• does it happen all the time or just when you speak loudly or with lots of voice energy?
• does it only happen with both parties try to speak at the same time or just when one party is speaking?
• do both parties hear it or only one party?  Which party hears the distortion?

A couple of thoughts on this:

• Make sure the phones (and SPA8800) are all on the voice VLAN -- getting 10.x.x.x IP addresses by default.
• Perhaps the problem is on one of the FXOs in the higher port numbers.  -- for PBX style dialing (9 to get out for example), we always select the lowest available (and configured) port first.  You might try making some test calls to the phone numbers associated with the higher port numbers.  If you can't direct dial these ports, you can put a call in talk on the first port then make another call and put that in talk and so on until you have all ports in talk.
• Do you hear this on SPA phone to SPA phone calls to or just when going over FXO?

Chris

[emil]

Yes the phones are on the voice vLAN. I have tested the phone lines from the demarc and I do not hear any problems.  I do know that it does happen from SPA to SPA but not as often as the outside lines.  I will try the volume suggestion and let you know if it helps.

[emil]

here is what I have found out

Can you be a little more specific in what garbled means to you?

• are you hearing echo or sound like you are in a tin can? YES
• are      you hearing choppiness like certain syllables are getting cut out? YES
• does it happen all the time or just when you speak loudly      or with lots of voice energy? IT DOES NOT HAPPEN ALL THE      TIME, BUT IF THE RECEIVER IS HELD FARTHER FROM THE MOUTH IT QUIETENS THE      EFFECT SLIGHTLY WHEN THIS IS OCCURRING.   WE HAVE NOT REALLY      TRACKED VOICE ENERGY ON THESE CALLS.  EVERY PERSON TENDS TO SPEAK IN      A NORMAL TONE.
• does      it only happen with both parties try to speak at the same time or just      when one party is speaking?      USUALLY WHEN ONE PARTY IS SPEAKING
• do      both parties hear it or only one party? USUALLY ONE PARTY HEARS IT, BUT SOMETIMES BOTH PARTIES      WILL HEAR THE ECHO.  WHEN THE PHONE PRODUCES A ROBOTIC VOICE, ONLY      ONE PARTY HEARS THIS EFFECT.    Which      party hears the distortion?  IT VARIES FROM CALL TO CALL – EITHER THE CALLER OR THE      RECEIVER.

[Christopher Edgeworth]

Hi,

If you are having this bad audio on SPA phone to SPA phone we need to get a case open with the Cisco Small Business Support Center.  They can enable some tools to capture Wiresharks and audio captures so we can see what is happening with your audio.

Let us know what you find in adjusting the SPA phone volume.  (keep in mind there are several independent volume levels (handset, speaker, and headset)).

Chris