atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Telecom Service & Providers VoIP / POTS humming problem

Line 1: Verizon Fios POTS
Line 2: Vonage VoIP

I have a Panasonic 2 line phone that handled them both with no problem for a month or so. Today, the POTS line started giving me a horrible humming noise. The 2 line phone is the only phone in the house. There is a fax machine on line 1 and a postage meter on line 1 - unplugging them makes no difference.

Here's what I've tried:
Connect regular phone right to port on Fios box - no hum
Disconnect all equipment - POTS still hums
L1 POTS / L2 empty - hum
L1 empty / L2 POTS - hum
L1 VoIP / L2 empty - no hum
L1 empty / L2 VoIP - no hum
Reverse tip&ring on either - no change

I can't seem to understand why it would work for a month and then have a problem now.

There is another POTS line in the house. If I connect both POTS lines, but no VoIP, there is no hum.

I've now disconnected the wiring for three unused jacks and I've stripped out the L2 wiring going to the fax and postage meter jacks - essentially stripping the system to only what I absolutely need. It worked for about a minute, then the hum came back, worse than before.

Luckily, the VoIP is the business line and is still working. Help me figure out some next steps. Thanks.

So I disconnected the postage meter and the majority of the hum went away. I'll call pitney bowes about a replacement. Does anyone have any idea of why this machine would affect the POTS line and not the VoIP line? Anything I can try before sending the equipment back?

If you're using a 4 pin line cord try a 2 pin. I've seen modem and credit card machines that induce noise into the line when a 4 pin cord is used.

I swapped the cord out and it didn't change the hum. I would just put the postage meter on the VoIP line, but it doesn't seem to function over VoIP.

Sounds like you have a ground on one side of your wiring or at least a problem with it. Disconnect everything and check each pair for shorts to each other and ground.

-Hal

2 comments: 1 serious, 1 in search of humor.
1. Has it recently rained a LOT in your area? If so, is the hum going away as the ground dries out. If so, it's a telco problem, but they will NEVER, EVER fix it!
2. It hums because "It doesn't know the words!" (Rim shot, PLEASE) John C.

If the noise is being induced by something like your postage machine before the the IP traffic is converted to analog voice that would make sense. ... Data "1's and 0's" could care less about some noise. As long as it can read the marks (a 1 or no 1) it will convert it to the analog voice.


JOHN!!!!!!! ... Errr... dang it. EVERYTIME, it gets me. You would think by now I wouldn't think that was funny! :rofl:

It is likely that a postage meter, fax or analog modem won't work on any VoIP line. The compression algorithms used in VoIP don't play well with analog data transmission. That is just a characteristic of IP that we need to learn to live with or simply not use it.

Just because IP appears to cost less doesn't mean that it does everything. This is a case of the proverbial "You get what you pay for".

It has rained a ton in the last week... if it goes away when it dries out, I'll let you know. However, the POTS is via FIOS, so there is no copper line outside of the house to be affected, just fiber optic.

I find that if I plug in the computer modem into the POTS line I get the hum as well. I'll try to get a voltage meter and test the lines to find either a short or a ground or something going on. Any suggestions for how to do that?

So I haven't gotten around to doing any testing this week and it has continued to rain heavily - and the hum/buzzing has gone away! Strange.