can you identify this mystery item?

That's from the U.S. Marshall's Service used to intercept cell phone communications.

Looks like a remote thermostadt sensing unit. To confirm, you might want to confirm (or have someone confirm) the wires attached to it are similar to the wires going to your thermostat. If that is what it is, it acts in conjunction with the thermostadt to ensure that the "remote" room is also kept at the same temperature as is the room where the active thermostadt is installed.

Thanks, oldgreyhair. None of the apartments in the bldg. have thermostats. Heat is by radiator and no central air is allowed.

Odd. When the electrician was there did he apply a voltage meter to the wires to determine whether it is, in fact, active or out of commission? I assume the wires appear to low voltage DC? You might want to remove the unit from the wall to determine any writing/name of manufacturer on the reverse side?

If the wires are not low voltage DC, or if you are not handy on these things, then best to just leave it be....

>If the wires are not low voltage DC, or if you are not handy on these things, then best to just leave it be....

Don't F with the feds.

Even though it's steam heat in the building, it could still be a temperature sensor used by the boiler control. The traditional method is to just have an outdoor sensor but it's not uncommon to add indoor sensors as systems are modernized.

I'd be inclined to agree with flarf. My guess it is still a remote thermostadt sensor. I understand your building was built in 1936. Whatever is pictured is a fairly recent installation. It could be that your unit (and maybe a couple of others possibly) were selected as the "regulating" apartments. Unless proven otherwise, I'd assume it is operational.

prop, it looks to me kind of like the old fashioned doorbell speakers. When one rang the doorbell, it would sound thru a small box in the apartment to alert the owners…..maybe no one ever removed it after all these years, but just disconnected the wiring?…..

Thanks, everyone. I will pass on your suggestions. The contractor just sent me an email. "Since no one knows what it does, just in case in the future for some weird reason someone is looking for it, we will just cap the wiring and conceal the box on the wall (plastered over). "

I will ask if they did a voltage meter test on the wires. Meanwhile, here's a new look inside: I just went into the apartment and the cover is off -- so now you can see the "innards."

http://i62.tinypic.com/i1ik8y.jpg

That's all !??? There's no control device inside? Well then you have your answer. Before capping, test for voltage. Looks like a phone line from my view. Why it was contained in the cover you have is the mystery.

Pretty funny, especially since the cover was attached with tamper-resistant screws.

Use the second lock on the front door tonight.

We may never know the answer. . . but something "phone" related may indeed be what is is. If it's not the original doorbell, a few people are suggesting that it may have been the original building intercom.... except it has no buttons or anything to press to respond.

ok..

Oldgreyhair, about testing the wires, the contractor says, "There is no power, so signals, nothing. Whatever it was there is dead." So maybe it is the original intercom or some sort of lobby announcement box -- like if there was a fire in the building. He says he's capping the wires, concealing the box and plastering over it. Maybe I should hide something in there and turn it into a miniature time capsule.