Solved: Tinny Voice Quality on outgoing and incoming calls - PRI

bwilloby46 · ‎01-20-2009

Using a 2811 as h323 gateway. All was working fine until a few days ago. OUtbound and inbound calls on Verizon PRI started to have a tinny sound. IP phone to IP phone internally has exceptional voice quality. Only outgoing and incoming calls from PRI have a tinny sound. Can anyone shed some light on what maybe causing this? Thanks.

Nicholas Matthews · ‎01-20-2009

Generally speaking audio problems come from five places:

1) Your Endpoints

2) Your DSPs

3) Your IP Network related problems.

4) Interference/noise/echo from your analog lines

5) Other people's DSPs/networks/endpoints

1) You can try upgrading the Cisco phone firmware. Since this firmware was working, I don't expect this to be the problem. Maybe the users upgraded to wireless headsets?

2) This really requires TAC to find out. Your DSP firmware version should be fine though in 7g. Sometimes replacing DSPs will solve audio problems, but not nearly as often as people believe.

3) The jitter values and packet loss are good. If the latency is below 150ms, you should be fine

4) Hard to tell - you can try switching known good lines with known bad lines. See if good calls go out one T1, but bad calls go out another. Sometimes you don't have this luxury.

5) My least favorite. Providers can be very bad about admitting problems on their lines. They will generally send an engineer out, he'll make a couple of test calls with a butt set, and that's the end of it. Better hope your problem happens often.

hth,

nick

View solution in original post

Kenneth Mohammed · ‎01-20-2009

Hello,

Do you see any errors when you do "show controller t1" (slip secs, errored secs, etc)? Did you have Verizon intrusively test the circuit? If so, what did they say. Also, did you try to bounce the t1 controller? Just a few suggestions to try to help isolate the issue.

Hope that helped, if so please rate.

Nicholas Matthews · ‎01-20-2009

Quick things to check:

-press '?' twice quickly on your IP phone during a bad call. Check out the max jitter, discarded and lost packets

-'show controllers t1', all the numbers should be 0.

What IOS version are you on?

You can also check out this doc, it may help.

hth,

nick

bwilloby46 · ‎01-20-2009

Running 12.4(7)g

Made an external call and everything looked pristine except for max jitter was 8. No lost packets, no drops, 20 ms latency. Working on Voice Gateway access. any thoughts?

Kenneth Mohammed · ‎01-20-2009

Once you get access to the gateway, do "show controller t1" and check for errors, and try doing shut/no shut on the t1 controller. If that doesnt work I would have the service provider test the PRI.

Hope that helped, if so please rate.

bwilloby46 · ‎01-23-2009

sh controllers t1

T1 0/0/0 is up.

Applique type is Channelized T1

Cablelength is long gain36 0db

No alarms detected.

alarm-trigger is not set

Soaking time: 3, Clearance time: 10

AIS State:Clear LOS State:Clear LOF State:Clear

Version info Firmware: 20060707, FPGA: 13, spm_count = 0

Framing is ESF, Line Code is B8ZS, Clock Source is Line.

CRC Threshold is 320. Reported from firmware is 320.

Data in current interval (5 seconds elapsed):

0 Line Code Violations, 0 Path Code Violations

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Total Data (last 24 hours)

0 Line Code Violations, 2 Path Code Violations,

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 1 Degraded Mins,

1 Errored Secs, 1 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

I have bounced the interface several times and even rebooted the router. no luck. Any thoughts? Bug maybe?

Nicholas Matthews · ‎01-23-2009

I would get your provider involved, and try to get a packet capture. It doesn't look like you have any glaring issues. Check out my previous post, and try upgrading/downgrading IOS and phone firmware versions, make sure users aren't on wireless headsets, etc.

-nick

bwilloby46 · ‎01-23-2009

no users on wireless. we are planning to upgrade IOS versions from 12.4(7)g to 12.4(20)T on this gateway very soon.

Nicholas Matthews · ‎01-20-2009

Generally speaking audio problems come from five places:

1) Your Endpoints

2) Your DSPs

3) Your IP Network related problems.

4) Interference/noise/echo from your analog lines

5) Other people's DSPs/networks/endpoints

1) You can try upgrading the Cisco phone firmware. Since this firmware was working, I don't expect this to be the problem. Maybe the users upgraded to wireless headsets?

2) This really requires TAC to find out. Your DSP firmware version should be fine though in 7g. Sometimes replacing DSPs will solve audio problems, but not nearly as often as people believe.

3) The jitter values and packet loss are good. If the latency is below 150ms, you should be fine

4) Hard to tell - you can try switching known good lines with known bad lines. See if good calls go out one T1, but bad calls go out another. Sometimes you don't have this luxury.

5) My least favorite. Providers can be very bad about admitting problems on their lines. They will generally send an engineer out, he'll make a couple of test calls with a butt set, and that's the end of it. Better hope your problem happens often.

hth,

nick

paolo bevilacqua · ‎01-23-2009

This pretty much said it all. 5 again for you Nick.