Line noise Hummmmm !!

[musicman50]

Hey Everybody,
My first post here

Question:
Can someone give me some tips on reducing the hum on my phone lines ??

I just purchased a Voice Pro VP206 on eBay, and it seems to pick up the noise on my lines. I have lots of home automation equipment, modems, routers, phones, all interfaced to one another, and there is some line noise, but the VP206 seems to grab all of it on its Voice mail function.

Any suggestions to reduct the noise very apperciated..

~Phil~

 

[macphoneguy]

Humm, can be the Easy or difficult to "fix" My first thought is to follow the Kiss principal, If the Line Has Humm, disconnect it from the Respective Devices (like the VP206) it's plugged into and either Add or Take away the Devices one at a time till you either Have no devices hooked up or everything disconnected, except perhaps a single line telephone, if you still have hum with nothing hooked up usually that is a Telco issue with Qwest, Verizon, SBC or whomever provides your dial tone usually one of the Devices is doing it, the other thought is to look at the Line Cords/Wires relative to any AC sources, as I have had a number of instances where there was Humm and one side of the wire was partially touching ground, this usually involved taking the Phone Jacks apart to look inside, also removing any 2-1 Adapter/Splitters

 

[musicman50]

Thanks Macphoneguy,
I did remove most of the equipment today, and still found line noise, but I also remembered 4 years ago when I had the same problem during rainy season, and interestingly it has been raining for several days.. I think its a bad telco problem. And the VP206 just amplifies the noise.

Thanks again for your ideas..

 

[geraldshort]

There could be another issue:
AC noise induction through the phone lines or faulty wired electrical circuit.

AC HUM:
If the filters on board are not big enough you could be getting this problem.
AC hum needs to be filtered to ground.
SNIX devices remove this. I have a few if you want to test.

Test dial tone at the MPOE without the phone equipment connected, if no sound with a standard phone, reconnect PBX equipment without any other devices attached. If you now hear hum it is a problem with the PBX filters.

AC WIRING:
this can be caused by AC wiring faults also, buy a plug in AC tester or hire an electrician to inspect. the cheapest way to test is plug in a UPS if you have it. Thay will report errors in the AC wiring usually.

Gerald

 

[doktor]

When we have this kind of problem, we follow these guidelines:
-Make sure that the lines inside the building are of the type twisted pair.
-The (any!) line should not be rolled up. Doing so, it will act as an antenna.
- Use a proper grounding for the switch or PBX. The grounding cable has to be followed all the way to the building main ground point (often in a cellar, where the power distribution frame is located.)
- In some cases use ferrite cores, and turn your ISDN/PSTN cables 2-3 times around these ferrite cores.

- In harsh environment (e.g. workshops with welding mashines etc.) use shielded cables, of course these cables have to be twisted.

Hope that this can help you.
Best regards from the Doktor.

 

[musicman50]

WOW !! What an awsum place this is !!
Thanks everyone for all the great information.
I'm getting started this weeken and try the suggestions out..
Thanks again everyone..

~Phil~

 

[orypecos]

I had a system with hum and it was that the large electrolyic capacitors in the power supply had dryed out cuz they were old.
ANother problem that causes hum is not having the same negative ground potential at the ac input of all of the devices. If u pull the breakers on all the equipment at the main building power panel and check to make sure all the power is gone with a multimeter, then set it to ohms and check to see that there is zero ohms between all the grounds of the ac outlets. If u are not familiar with use of a ohmmeter then u might get someone that is so u don't blow up the multimeter or electrocute yourself.