What happened to our phone outlet?

Kitchen phone: combination answering machine / cordless phone unit, wall-mounted.

About 5 years back, our household phone sound quality went wayyyyy downhill suddenly - lots of static no matter which phone you were on. We found that the cord that connects the kitchen phone to the phone outlet had some slightly blackened spots. We replaced it, phone quality improved. A few weeks later it got bad again, we had an electrician out for several jobs, and he replaced the phone outlet, and all was well.

Fast forward to a few weeks ago: same thing happened. Phone quality suddenly got bad, slightly blackened phone cord plug, replaced that, quality got bad again, so now we’ve got the phone on another outlet, in another room.

If it’s relevant: 5 years ago, we had regular phone service, and now it’s FIOS (in case that affects the likelihood of a power surge).

Note that it’s the same outlet both times,; we have not had this happen with other phones in the house.

Any idea what’s going on?

You mention that this is the jack that has an answering machine on it. I am thinking that somehow it is getting power surges from the unit that is too strong for the outlet. Is there some sort of surge protector between the jack and the machine [my surge protector that I jacked my fax machine through had both the protection for the electrical jack into the wall, but you also jacked your phone line in, and then another phone line out to the fax machine so nothing was direct from wall to machine, it all went through the surge protector.]

You replaced the cord, you replaced the jack, therefore what is left - problem on the other end of the wire, or the phone itself. Given that this is a plug in phone (since it is cordless/has an answering machine), I’d suspect the phone itself rather than the wiring/connection on the other end. Were I you, I’d be getting a new phone system & a new surge protector with the phone jack protection - both to plug in the RJ-11 phone cables, and to plug the cordless phone’s power cord itself into - could be surges in your house electrical through the phone that caused it the first time.

We did replace the phone, 5 years ago, before we figured out that it was the jack that had gone bad. So the current phone is not the same one that was on the line 5 years ago.

But, it is plausible that it’s related to a surge in the electrical line (the feed to the answering machine).

Now, the power to the phone (the answering machine, that is, not the phone line) is not on a surge protector, it’s just plugged into a regular wall outlet. I should try to get a small surge protector to cover that. Not sure how we’d do a surge protector on the phone cord itself, since the phone is wall-mounted; I know some power strips have phone-line protection as well, maybe we could run a cord down to that from the wall, and back up to the phone, if there’s enough room to snake it in the phone’s mounting bracket.

try those two things.

surges can get into phone and power wires in your house with just nearby lightning strikes. other things can cause too.

Surge protector would, at best, only cure symptoms. Best is to find the problem. And yes, FIOS significantly changes the analysis.

Easiest way to start is to go to where all interior phone wires collect. Get or borrow a multimeter (even $5 in Harbor Freight). Set the meter to a 200 VAC setting. Temporarily unplug the phone line from where it connects to the FIOS box. Measure between the two (wire) pair. And measure from each wire to any receptacle safety ground or copper water pipe. Voltages should be near zero. Actual number is important since that number contains information you do not realize is important.

Repeat those measurements with the meter in its 200 VDC settting.

Next, set the meter to its highest resistance measurement (ie 1 Megohm or 10 Megohm). Again, measure that resistance between the wire pair. And from each wire to the safety ground or pipe. Also report those numbers.

Those numbers will quickly identify or exonerate a large number of suspects. Only then can we move on to other suspects.

Surges do not enter phone lines via nearby strikes. If it was a surge, then lightning found a direct connection to that phone line. Inspection is important. For example, does any phone wire connect to some nearby building (ie garage)? Does it go anywhere outside the building? If yes, then a direct strike to a tree could be a direct strike to the phone line.

Also useful is to trace interior phone lines. Does it connect to some device that looks like connecting studs? Anything that looks like this?
Or connected to anything else that does not appear to have a specific function?