sundance-communications.com/forum Forums TDM Business Telephone Systems Mitel Telephones & Systems Mitel 3000 60 Cycle Hum

I am wondering if anyone has had any problems with 60 cycle hum when using wireless headsets plugged into the headset jack on the Mitel ECX 1000 phones?

We recently installed a new system Mitel 3000 with 3 ECX 1000 phones. The KSU has 1 CO Line card (2 lines), Voice module 2 port, MOH adapter using "The Messenger MP3" by Audio Messaging Solutions.

We are having the problem on all three phones and the only way it seems to go away is when you unplug the headset from the phone. We even tried to use a different model of wireless headset (Plantronics CS70) and the noise still persists.

We have essentially swapped out everything with no success in getting rid of the noise. We even removed the KSU and headset from commercial power and run them on battery backups and the noise is still there.

The noise is not present on any of the lines at the demarc.

We can plug a phone and headset into the KSU with the supplied line cord and the noise goes away but if we run a 100ft or so of line cord on the floor from the KSU to the office location the noise is present.

Any ideas that I might try would be greatly appreciated.

You may have a cable running parallel to a power cable, or you may have poor KSU grounding. KSU should be grounded to the Telco ground, NOT, repeat, NOT to the electrical ground for the building.

For that matter, you may have a poor building ground and the entire building frame has become a 60 Htz transmitter!

Thanks guy
These are all good things to check. Currently I have the KSU grounded to the electrical. Gota find the telco ground. It is one of those strange buildings that is built on the side of a hill so you walk into 2nd floor of a 4 story building. It is also readily apparent that the building has had water issues so maybe the electrical ground is corroded...

Do you think I can ground to a water pipe? that might be easier.

Water pipe is the same as electrical ground (usually) and it only works if you are SURE that the water main has not been replaced in PVC at some point. I do not recommend it, and I don't believe that it's legal to use the water pipe as your main ground.

At the MPOE there should be a ground block -- copper with lots of screws and wires on it, very obvious -- and if that's not at your KSU location, you could try attaching unused pairs to the ground, then attaching the other end of those unused pairs to your KSU. Not ideal, but it may work. This is not advice.

Best is if you can get a ground wire all the way from KSU to MPOE, though (and the cablers should have brought some sort of ground with them to the IDF where you have your KSU).

Without seeing the building it is hard to give you a definitive answer.

tg is right about the ground.

You think about what you are doing. You sure don't want to wind up being building ground for the entire building! Been there, done that, replaced a BUNCH of phone parts. All because they didn't believe their building ground was inadequate/inop. I drove a ground rod and managed to become building ground through the chassis ground on the KSU. How ever, their computer network REALLY took it in the shorts, so they had a REAL electrician check the ground and he proved me right and their jackleg wrong!

Kevin, I'm gonna recommend that you get a real electrician, and a real phone guy, out there on site. Service calls for either one will be cheaper than the replaced parts.

Also, unless they've changed it, I think that as little as a 1 Volt difference between building ground and telco ground will void your Mitel warranty. You REALLY want this building checked out right. Honest.