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uc520 noise on line

jjoseph01
Level 3
Level 3

All, I have another issue with noise on a line. This can be either internal calls or internal to external calls, where they hear a sound like "sssshhhhh" (like an ocean sound, but constant). Anyone know how to get rid of something like that? Much appreciated.

32 Replies 32

paolo bevilacqua
Hall of Fame
Hall of Fame

Which phone FW do you have ?

Sorry, its on a UC520 again.

The phones have their firmware, you can see the level from either router or phone itself, from settings -> device info, or again, accessing the http server at phone's IP address.

Hi. i had the same problem on my UC520, I'd forgotten to set the cptone under the voice port

The OP ha the problem for internal calls also, meaning voice-port is not involved.

My apologies beveilacqua, I have a bad habit of taking FW as firewall and not firmware. Again, my apologies. Im looking now, and see the following in the flash for the 524s:

cp524g-08-01-07.bin

Hi, there is a tarfile on CCO, CME area, phone laods 7.0.2, can you check if it contains a newer firmware - I'm not sure.

I've downloaded the tarfile and it contains FW 8.1.13 for the 524, you should try that before anything else.

ok, I just found out from the guy who installed this that there is a 7931 on here also that does the same thing. Not just 524s. Sorry, I didnt know that. I appears that both types of phones, 524s and 7931s are having this issue. Still think it might be a firmware issue?

That is quite strange, does it happen for all calls or just sometime? Can you confirm it happens for both internal and external calls.

Yeah, I called her a few moments ago. She says it happens on all phones, all the time. Both on internal to internal and to internal to external. I setup a ip communicator phone across a vpn and I DONT hear the noise. She says she hears this "crackle" sound, like someone is wadding up paper. It was described to me by the engineer like a "ssshhhhhh" sound.

I talked to Cisco TAC about this. Im pretty frustrated at their response at this point. They tell me its a QoS issue. I cant hardly believe that since they have 4 ip phones total, and 4 pcs total, all connected to this UC520. Im not sure I believe that, since there is very little traffic going on on the network period.

This is bizarre.

First - I don't know of any bugs on the 524 related to voice quality, and I've done a ton of testing on those phones.

We can play the elimination game here:

IP phone to IP phone means these things are NOT the problem: UC520 (in any form), including voice ports, CP tones, IOS versions, controllers, scripts, or configuration (unless you have MTP configured under the ephones, or this call is hairpinned through a SIP/analog trunk). IP phone to IP phone on a LAN only includes these 3 things: The phone, wiring between the phones and switches, and the switch. The traffic is point to point here. (The more likely explanation is that it doesn't happen.)

2 different phone loads, same problem: This means it is not a firmware issue on either of the phones. (Technically there's an incredibly small chance).

VPN works with communicator: confirms voice port and UC520 again, similar to IP phone to IP phone.

This doesn't leave much. Some possible causes still left:

-Every phone being defective

-Something wrong on the switch leading to packet loss (like QoS)

-Ambient Noise

-Headsets

-Bad Handsets

Some tests to eliminate these:

-Get a packet capture from the back of a phone for a bad audio call, and decode the audio. See if there is packet loss or if it sounds fine. This will clear the switch problems if the audio sounds fine.

-Use a known good phone and see if it has the problem.

-Don't use headsets

You can use part of this post to decode the G.711 audio stream:

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Unified%20Communications%20and%20Video&topic=IP%20Telephony&topicID=.ee6c829&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40^1%40%40.2cd249ca/3#selected_message

-nick

Nick detailed various possibilities, I always like to take shortcuts, can you have the 7931 make an external call and check, that will eliminate the 524s from equation.

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