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Static - Where to start troubleshooting?

We have a CCM 4.1(3) system that's been in place for over 3 years now. The last few weeks I've been getting complaints of static on calls and this past weekend I was getting complaints of dropped calls. We have 5 PRIs going into 2 6608 blades in 2 different core switches. What is the best way to figure out where in the world that static is coming from??? Save me!!! Thanks!


First thing I would do is identify the power users that are encountering the problem most often, then giving them the QRT Softkey so that they can begin flagging calls that have poor quality. Once you have a decent set of bad calls, find the common thread. If it's a static problem, the first thing you look for is the PRI port that they are using and see if one port is the source for most (or all) of the problems.


I've had them record the calls and I tracked them back to the PRI and port. It's not always the same port. Usually occurs on the same PRI, but it's our 1st outgoing PRI. I found some of the calls went out on another PRI, but it was the 2nd Outgoing so that part makes sense.


I've worked with the LD carrier and our local carrier and they are both saying all of their stuff is testing clean.

Does anyone know of ANYTHING on our end that could be causing the static? Sometimes it's one 1 end of the call, sometimes it's on both. Sometimes isn't LD calls, sometimes it's local, sometimes it's incoming and sometimes it's out going!


How many users is this effecting? One other possible point of static, where the voice traffic is not packetized, is between the handset and the phone. That is easy enough to test, however, but just switching to speakerphone and hanging up the handset.


It's effecting random users. Some days I might get 10 or 12 complaints, other days I might get 60 or 70. And it's not always the same person. The users are connected to different switches if that info is of any use to you.

I had one user place 3 calls the other day within about 5 minutes. I traced all 3 calls and they all ended up going out on the same channel of the same PRI. 2 out of 3 had no static. The internal call path should have been same the whole way throughout. That's why I'm thinking the problem is not on our end.

Could you explain the difference between using the speaker phone and the handset and how that tests the packetizing?


I had a user with a call with static and did a show port voice command while the call was in progress. Here's what I got:

Channel #5:

Remote IP address :

Remote UDP Port : 28176

ACOM Level Current : 460

Call State : voice

Codec Type : G711 ULAW PCM

Coder Type Rate : 20

ERL Level : 450

Voice Activity Detection : disabled

Echo Cancellation : enabled

Fax Transmit Duration (ms) : 0

Hi Water Playout Delay : 0

Low Water Playout Delay : 0

Receive Bytes : 3898880

Receive Delay : 35

Receive Packets : 24368

Transmit Bytes : 3899200

Transmit Packets : 24370

Tx Duration (ms) : 480590

Voice Tx Duration (ms) : 480590

I also looked at the Streaming Statistics on the phone while the call was in progress:

Remote Address

Local Address

Sender Joins 3937

Receiver Joins 3959

Byes 3958

Start Time 1213525520

Row Status Active

Name SEP001192847F70

Sender Packets 20154

Sender Octets -235254112

Sender Tool G.711u

Sender Reports 7895

Sender Report Time 1213565836

Sender Start Time 1213525520

Rcvr Lost Packets 1

Rcvr Jitter 1,63

Receiver Tool G.711u

Rcvr Reports 7895

Rcvr Report Time 1213565836

Rcvr Packets 20157

Rcvr Octets -303646631

Rcvr Start Time 1213525520

MOS LQK 4.5000

Avg MOS LQK 4.4926

Min MOS LQK 4.2512

Max MOS LQK 4.5000

MOS LQK Version 0.95

Cmltve Conceal Ratio 0.0001

Interval Conceal Ratio 0.0000

Max Conceal Ratio 0.0167

Conceal Secs 3

Severely Conceal Secs 1

Does any of that show a problem??? Thanks!


We are still having problems with static and some problems with dropped calls. I was able to get a copy of a voicemail that was static the whole call. You couldn't even hear the caller on the other end. And the end of the message you hear the caller hang up and the voicemail goes silent. After the silence there is a brief burst of noise and then the message ends. Is there any way to determine where the static is coming from based off of that? I've attached the voicemail message.


Not sure if you got this figured out yet, but one of our sites were having the same issue and the problem was related to the racks not being properly grounded. So here are my list of questions.

1. Is the equipment properly grounded?

2. How old is the building/wiring?


Verizon FINALLY admitted the problem is on there end. The whole calling area serviced by the CO has static problems.

Thanks for the info!


Do you know what the problem was with Verizon?  Did you find out what they fixed?  We have the same problem and need a solution.


It was a bad T1 between the office we went through to the central office. Once they took that T1 out of service, the problem was gone. The problem was effecting more than just us, it was affecting a whole portion of town that went through that office.


Thanks for the response.  We have the same type of static problem, just not as loud.  These were FXO ports but they were changed to a PRI but the problem is still there.  It's periodic and therefore hard to catch for troubleshooting purposes.  Did the other customers in the area complain about static also? How did you know the whole area was affected?  Did Verizon swap out cards in the CO?


It was a periodic problem with us also, but we had 70+ telerecruiters dialing out for 6 hours a day so the problem was frequent for us.

I don't know if anyone else ever complained to Verizon about the problem. I knew the whole area was affected because other co-workers and family that live in the area said "hey, I have that problem too!".



We are having the same problem with Verizon trunks.. Can you describe what Verizon did to fix the issue?