atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Telecom Service & Providers Strange hum problem has me at my wit's end... please help!

$277 is what their exclusive distributor quoted me for a single-line Super SNIX. And they said I'd need two -- one for each line. I guess if I have to spend some money on this problem, I'd rather try another $50 phone!

Read the post in "general" about chokes..I've bought them. In my opinion that is not your problem. Since we're talking 3rd party here I'll tell you they are about the same price as the phone for end of line chokes. Part number is in the other post.

If this were AC power induction you would have it no matter what. Wouldn't matter if one line or 10 lines were hooked up, you have it on each line. Like I said, you have more trouble shooting to do.

A cheap and easy solution!

After a few days of brainstorming trying to figure out how to completely isolate my telco line from my VOIP line, I thought about trying one of those RF phone jack extenders. The transmitter unit deals with whatever crap the phone company is sending and selectively transmits the voice frequencies to the receiver.

The receiver then emulates a clean phone line that is not referenced to ground anywhere which should not give me any sort of unbalanced, hum-inducing condition. This was my theory, anyway.

Well, $50 and a few minutes later, my problem was solved! I know this is not a "professional" solution, but look at what I am dealing with... a pieced-together kludge of a system! So what's one more kludgie piece??? Hey, it works great, I get to keep the (most likely, crappy) phone that I like, and I am happy. Just thought I would post this for anyone out there with a similar problem.

Thanks again to everyone for your input... it got my brain going and really did help.

Wow. Sure glad that I found this forum. I am having a very similar problem. 2 line AT&T phone (model 992). Separately each line is clean. When I add my VoIP line to the same phone as my POTS line I get hum on the POTS line. This is the second post that mentioned AT&T phone in the problem statement so it could be the root cause. I like the phone isolation solution using a "phone jack extender." Did you put it on the POTS line or the VoIP line. I would guess the VoIP side. I will be going to Radio Shack tomorrow and pick one up.

I went back and read your 1st remark. You went back to using 2 side by side phones. That is the ultimate test for the lines. If ok, it is the phone, or the cord. Some 2 liners use ac for intercom, and have a conference that ties lines together, or has a flat cord and needs a twisted, for noise and xtalk. They shouldn't interfere any more than 2 different phones. Pairs can be split and xsed with dead wires and pick up noise. Inbalance, and sounds like ground humm, but the 2 seperate phones would be noisy too.

Scott, it does not matter which line is isolated, however I would use it for the VoIP line. This way, in the event of a power failure, where you would lose the IP line anyway, you will still have your POTS line working on the phone in case of emergency.

Scott, contrary to the conflicting advice, it DOES matter which line you run through the "extender"... at least it does in my case. For the reason that Ed stated, I first ran the VOIP line through and connected the Verizon line directly to the phone. This resulted in the same bad hum on BOTH lines and non-working Caller-ID on BOTH lines as if the extender was not connected. So the only scenario that worked was to "filter" the Verizon line and direct connect the VOIP line.

Can you tell me what brand of extender that you used. All the one that I see use the AC powerlines to transmit the signals.

Thanks for the input. You are right... there was NO hum when using two separate phones. But the problem was not with the phone cord. And it had nothing to do with the AC power supply hooked to the phone, as the problem still existed with the power supply disconnected.

I suspect it has something to do with the simple internal electronics of the consumer two-line phone like someone had mentioned earlier. It was just not meant to marry the wildly variable conditions of the archaic switched telephone network with the relative precision of even such a simple device as the VOIP unit I have.

I am sure I could have purchased a more expensive phone or a commercial phone system (I am partial to the old Inter-tel Axxess, having maintained and programmed one for 12 years), but since I am just a guy in an office in my home right now, I wanted to get this thing working as quickly and cheaply as possible.

And during a power failure, I won't be working in here anyway because I need my computer for all the work that I do.

My AT&T 992 phone is a few days old. I can return it to Staples for another 2-line phone.

Any recommendations for a good quality 2-line phone that has a 2.5mm headset jack and caller ID?