question about "Network Interface" phone jack

[wylbur37]

After living in the same place in New York City for years,
I recently moved to another place (also in New York City).
The room I moved to has an existing phone jack but it looks different
from the old square-ish ones I'm accustomed to.
(The old ones consisted only of 4 terminals inside the case).
This new one is rather rectangular and has a label on the outside
that says ...

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?

 

[Michael A. Terrell]

wylbur37 wrote:

After living in the same place in New York City for years,
I recently moved to another place (also in New York City).
The room I moved to has an existing phone jack but it looks different
from the old square-ish ones I'm accustomed to.
(The old ones consisted only of 4 terminals inside the case).
This new one is rather rectangular and has a label on the outside
that says ...

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?

Its what it says it is: the network interface. It is the point where
the telephone company's wiring stops and yours starts. It is not
intended to be used for a telephone jack. Also, you are not supposed to
be inside the box, other than to plug in a telephone to verify your side
of the wiring before calling for repair service. As far as the circuit
board, why would you want to remove it?

--
Link to my "Computers for disabled Veterans" project website deleted
after threats were telephoned to my church.

Michael A. Terrell
Central Florida

 

[Carl Navarro]

On 24 Jul 2005 19:11:21 -0700, "wylbur37" <wylbur37nospam@yahoo.com>
wrote:

After living in the same place in New York City for years,
I recently moved to another place (also in New York City).
The room I moved to has an existing phone jack but it looks different
from the old square-ish ones I'm accustomed to.
(The old ones consisted only of 4 terminals inside the case).
This new one is rather rectangular and has a label on the outside
that says ...

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?

I give up

* Is it really necessary? (How come the old-fashioned jacks
didn't have this?)

Perhaps electronic surge protection

* What if I were to disconnect it?

Why would you want to, it ain't broke.

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?

Yes

* What is it used for?

Corrosion control.

Carl Navarro