Question About "Network Interface" Phone Jack

Network Interface *Caution Disconnect plug from this jack during installation and repair of wiring. *Testing Plug working phone directly into this jack. If phone operates, fault is in wiring. If phone does not operate, call repair service.

When I opened the case, I noticed that the red and green wires (the only ones that will be actually used by the telephone itself) are also connected to a little circuit board whose most conspicuous component is a yellow cylinder-shaped object (about 3/4" long and about 3/8" diameter) with the following markings ...

250V TI 0.47 MFD +/- 10%

  • What is the purpose of this circuit board?

  • Is it really necessary? (How come the old-fashioned jacks didn't have this?)
  • What if I were to disconnect it?

Also, when I looked inside the jack itself (the hole where you would plug the phone into), I noticed there's some strange-looking gunk inside. It's clear-colored and has the consistency of rubber cement.

  • Is this something that's supposed to be there?
  • What is it used for?
Reply to
Loading thread data ... Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.