web statisticsweb stats Business Phone Systems Tech Talk Forum - VOIP & Cloud Phone Help

Business Phone Systems

Previous Thread
Next Thread
Print Thread
Rate Thread
#572974 06/12/14 09:37 AM
Joined: Aug 2002
Posts: 1,068
Likes: 1
jsaad Offline OP
Member
OP Offline
Member
Joined: Aug 2002
Posts: 1,068
Likes: 1
I have a 200EL in a hotel. I have two trunks on different cards in different bays with a loud chatter noise on the trunks. This only occurs if you make a call from the mitel side. The trunks are good from the telco side.

I've replaced LS/GS cards and changed the pair and the 25 pair cables and added more ferrite cores. I've even put the cards in a different bay. Same problem

I believe there is some sort of interference from a fire alarm cable but I can't find it.

Do you have any recommendations?

Atcom VoIP Phones
VoIP Demo

Best VoIP Phones Canada


Visit Atcom to get started with your new business VoIP phone system ASAP
Turn up is quick, painless, and can often be done same day.
Let us show you how to do VoIP right, resulting in crystal clear call quality and easy-to-use features that make everyone happy!
Proudly serving Canada from coast to coast.

Joined: Feb 2006
Posts: 1,716
Member
***
Offline
Member
***
Joined: Feb 2006
Posts: 1,716
Remove the CO line from one of the trunk ports and take a know, good line from another trunk port and connect it on the trunk port in question. Make a call on that trunk. If the call has no "chatter" then the problem is not the Mitel trunk port.

What make you think there may be interference with a fire alarm cable?

Rcaman


Americom, Inc.
Where The Art And Science Of Communications Meet
Joined: Aug 2002
Posts: 1,068
Likes: 1
jsaad Offline OP
Member
OP Offline
Member
Joined: Aug 2002
Posts: 1,068
Likes: 1
The problem follows the line, not the mitel port. So somewhere there is some sort of interference that the Mitel picks up. This is an old multi building hotel, trunks come from two buildings away on a combination of old aerial cables. I've changed pairs where I can and there is still loud chattering noise only on the mitel side, though. Directly on the trunk with a butt set, no noise.

Joined: Aug 2005
Posts: 2,125
Member
Offline
Member
Joined: Aug 2005
Posts: 2,125
I hear you saying that the trunks are all good at the demarc. You say that the problem follows the line, not the port, so I assume that you've isolated specific analog trunks that are making the chatter.

Since it does not follow the port, it is not in the Mitel. Since it's good at the demarc, it's not at the Telco. This is a building inside-wire issue.

A couple of things you can do to cut to the chase:

1. Run a new cable(s), preferably CAT 6, from the MPOE to the switch. Use this cable(s) for all affected trunks.
2. Busy out the affected trunks. The affected trunks will be in the outbound trunk group, in case you haven't completely isolated them yet (because you say that it happens with calls originating in the Mitel only).
3. Look for sources of radio interference.

Interference can be a tough issue. I had a call once on a office with crackling and hiss over their speakers, overhead and on the phones. I found a power cord going through the MDF loom. I separated the power cord, and suddenly music was coming through all the speakers -- they had background music turned on, and the power cord had been overriding it with hissing.

Best of luck.

Joined: Feb 2006
Posts: 1,716
Member
***
Offline
Member
***
Joined: Feb 2006
Posts: 1,716
Here is where a good, old fashioned, line quality test tool comes to play. I have a Triplett Model 7, Dynatel 965TD and a Sidekick 7B. Each has a unique way of testing line quality and revealing hidden troubles. Even though it "sounds OK" in a butt set, any of these instruments will reveal if there is a real problem.

That said, you may have a grounding issue that is playing tag with the Mitel. I'm sure you have the Mitel grounded BUT is the cable ground feeding the Mitel with the CO pairs, grounded AND bonded? The Telco brought the pairs to a demarcation on a cable, most likely a PIC cable with a metal foil shield bonded to a ground. Is that bonded ground carried all the way to the Mitel? My guess is that it is not.

The solution may be as simple as replacing a section of cable that is missing that bond or as complicated as installing transformers and chokes to bleed off the offending imbalance. In the good old copper days, the telco fought the noise battle with load coils and other ingenious methods of filtering out imbalances. Today, especially with high cap circuits, load coils and other filtering transformers are taboo. But, for your situation, this may be the solution.

Rcaman


Americom, Inc.
Where The Art And Science Of Communications Meet
Joined: Aug 2005
Posts: 2,125
Member
Offline
Member
Joined: Aug 2005
Posts: 2,125
Here's a tech bulletin by Sandman that might be helpful.

https://www.sandman.com/rfbull.html

Joined: Aug 2002
Posts: 1,068
Likes: 1
jsaad Offline OP
Member
OP Offline
Member
Joined: Aug 2002
Posts: 1,068
Likes: 1
Thanks. I have a plan to replace about 150Ft of cable. The lines come out of a channel bank 2 buildings away. I tried some old filters from Sandman from many years ago, no solution yet.


Link Copied to Clipboard
Forum Statistics
Forums84
Topics94,262
Posts638,693
Members49,757
Most Online5,661
May 23rd, 2018
Popular Topics(Views)
211,098 Shoretel
187,703 CTX100 install
186,793 1a2 system
Newest Members
BPopilek, Rich F, LewisR, TDKs79, Buttinset
49,757 Registered Users
Top Posters(30 Days)
dexman 18
Toner 14
TDKs79 8
Who's Online Now
1 members (Curlycord), 111 guests, and 241 robots.
Key: Admin, Global Mod, Mod
Contact Us | Sponsored by Atcom: One of the best VoIP Phone Canada Suppliers for your business telephone system!| Terms of Service

Sundance Communications is not affiliated with any of the above manufacturers. Sundance Phone System Forums - VOIP & Cloud Phone Help
©Copyright Sundance Communications 1998-2024
Powered by UBB.threads™ PHP Forum Software 7.7.5