If you open up a BT telephone socket you see a few electronic components, they seem to me like capacitors and a resistors.

What are they for?

More importantly, can I do without them?

I am thinking of connecting a telephone to a telephone line directly, without a socket and the corresponding plug. This way I avoid the socket which is visually intrusive in my particular location. I do not mind having a fixed cable sticking out of the wall.

Thanks,

Antonio

Hi Antonio

On Sat, 21 Jan 2006 17:24:04 +0000, asalcedo
wrote:


If you open up a BT telephone socket you see a few electronic
components, they seem to me like capacitors and a resistors.

What are they for?

More importantly, can I do without them?

I am thinking of connecting a telephone to a telephone line directly,
without a socket and the corresponding plug. This way I avoid the
socket which is visually intrusive in my particular location. I do not
mind having a fixed cable sticking out of the wall.

Thanks,

Antonio

Assuming that this isn't a troll.......

Don't recommend that you disconnect the socket. It's known to BT as a
Master Socket - and the components in it are used as part of BT's
automated testing of your line.

I think that the Master Socket is actually BT's property - so if you
'fiddle' with it it'll fail the automated testing and they'll charge
you for reinstalling it...

Not a good plan !

Adrian

======return email munged=================
take out the papers and the trash to reply

In message , asalcedo
writes

If you open up a BT telephone socket you see a few electronic
components, they seem to me like capacitors and a resistors.

What are they for?

More importantly, can I do without them?

I am thinking of connecting a telephone to a telephone line directly,
without a socket and the corresponding plug. This way I avoid the
socket which is visually intrusive in my particular location. I do not
mind having a fixed cable sticking out of the wall.

The answer's you can't

Stick to crayons and soft objects - you're on safer ground

--
geoff

On Sat, 21 Jan 2006 17:24:04 +0000, asalcedo
wrote:


If you open up a BT telephone socket you see a few electronic
components, they seem to me like capacitors and a resistors.

What are they for?

More importantly, can I do without them?

I am thinking of connecting a telephone to a telephone line directly,
without a socket and the corresponding plug. This way I avoid the
socket which is visually intrusive in my particular location. I do not
mind having a fixed cable sticking out of the wall.

The master socket doesn't have to be co-located with the phone. You
can have it wherever is convenient in the house, and connect the phone
via there.

Remember though, that the master socket is the property of your
service provider, and you shouldn't be tampering with it yourself,
especially if you don't know what it does!

--
Frank Erskine

asalcedo wrote

If you open up a BT telephone socket you see a few electronic
components, they seem to me like capacitors and a resistors.

What are they for?

More importantly, can I do without them?

No.

I am thinking of connecting a telephone to a telephone line directly,
without a socket and the corresponding plug.

You could hide the master box in the loft or somewhere, and run a long lead
from it to the telephone.

--

mike

"asalcedo" wrote in message
...

If you open up a BT telephone socket you see a few electronic
components, they seem to me like capacitors and a resistors.

What are they for?

More importantly, can I do without them?

I am thinking of connecting a telephone to a telephone line directly,
without a socket and the corresponding plug. This way I avoid the
socket which is visually intrusive in my particular location. I do not
mind having a fixed cable sticking out of the wall.

Thanks,

Antonio


--
asalcedo

You can mount some versions of the BT master socket flat into a standard
wall mounting box. You can then run your telephone cable to where ever you
want youe secondariy sockets from there. The bt line voltage can hurt under
certain circumstances, if in doubt fit the new sunk in wall back box and
then ask bt to move the master socket.

In article ,
asalcedo wrote:
I am thinking of connecting a telephone to a telephone line directly,
without a socket and the corresponding plug. This way I avoid the
socket which is visually intrusive in my particular location. I do not
mind having a fixed cable sticking out of the wall.

You can get flush fitting master sockets to match your other electrical
sockets, etc. BT fit their nasty surface mounted ones because it's cheap
and quick.

--
*Why is it called tourist season if we can't shoot at them?

Dave Plowman London SW
To e-mail, change noise into sound.

On Sat, 21 Jan 2006 22:50:04 +0000, Owain
wrote:

asalcedo wrote:
If you open up a BT telephone socket you see a few electronic
components, they seem to me like capacitors and a resistors.
What are they for?

The capacitor blocks DC but passes AC. It prevents the bell
short-circuiting the DC speech current but passes the AC ringing current
to the bell.

The resistor puts a known resistance across the line even if there are
no phones plugged in. It enables BT to detect a line break during line
testing.

And the non-linear resistor clamps over voltage should it get across
the pair (I think)?

All the best ..

T i m

In message , T i m
writes
On Sat, 21 Jan 2006 22:50:04 +0000, Owain
wrote:

asalcedo wrote:
If you open up a BT telephone socket you see a few electronic
components, they seem to me like capacitors and a resistors.
What are they for?

The capacitor blocks DC but passes AC. It prevents the bell
short-circuiting the DC speech current but passes the AC ringing current
to the bell.

The resistor puts a known resistance across the line even if there are
no phones plugged in. It enables BT to detect a line break during line
testing.

And the non-linear resistor clamps over voltage should it get across
the pair (I think)?

You mean a transzorb ?

--
geoff

On Sun, 22 Jan 2006 00:39:10 GMT, raden wrote:

In message , T i m
writes
On Sat, 21 Jan 2006 22:50:04 +0000, Owain
wrote:

asalcedo wrote:
If you open up a BT telephone socket you see a few electronic
components, they seem to me like capacitors and a resistors.
What are they for?

The capacitor blocks DC but passes AC. It prevents the bell
short-circuiting the DC speech current but passes the AC ringing current
to the bell.

The resistor puts a known resistance across the line even if there are
no phones plugged in. It enables BT to detect a line break during line
testing.

And the non-linear resistor clamps over voltage should it get across
the pair (I think)?

You mean a transzorb ?

Wern't they the sworn enemys of the Cybermen? ;-)

Probably ..

T i m

Hi Tim,


Thank you for your explanation. It makes sense. I did not know that the ring is done with AC.

I have now done some additional research on the issue and understand the BT Telephone socket wiring.

The conclusion is that circuitry is not needed for my purposes, my line does not go outside.

Thanks,

Antonio

In article , mike
wrote:

You could hide the master box in the loft or somewhere, and run a long
lead from it to the telephone.

The loft can be inconvenient.

A previous occupant of our house had the master socket installed in the
loft. Last year I changed over from dial-up internet access to ADSL. On
the appointed day for ADSL to become active I plugged in the modem but
the sync light just kept flashing - no ADSL. I knew the modem was OK, it
had been working fine elsewhere but BT refused to even consider that the
ADSL line wasn't working until I disconnected all extensions and plugged
the modem into the master socket. Since it was an USB modem and not a
router I ended up having to lug the entire PC up into the loft just to
prove a point :-

--
Mike Clarke

raden wrote:

On Sat, 21 Jan 2006 22:50:04 +0000, Owain
wrote:
And the non-linear resistor clamps over voltage should it get across
the pair (I think)?

You mean a transzorb ?

The voltage limiting component in the NTE5 and the older types of master
socket is a gas discharge tube (GDT), not a semiconductor device. Think
of it as like a sort of heavy-duty neon - below the striking voltage
(which is 250 V, I think) it looks like a ~2 pF capacitor, if struck it
will clamp to a much lower voltage and will happily conduct kiloamps for
a short time (on the order of a hundred microseconds). It's there to
protect downstream equipment from transverse surges induced by lightning.

The GDT is not fitted in PABX masters.

--
Andy

Mike Clarke wrote


A previous occupant of our house had the master socket installed in the
loft.

Since it was an USB modem and not a
router I ended up having to lug the entire PC up into the loft just to
prove a point :-

Sods law strikes again.

(Haw, haw) ;-)


--

mike

On Sat, 21 Jan 2006 22:50:04 +0000, Owain wrote:

asalcedo wrote:
If you open up a BT telephone socket you see a few electronic
components, they seem to me like capacitors and a resistors.
What are they for?

The capacitor blocks DC but passes AC. It prevents the bell
short-circuiting the DC speech current but passes the AC ringing current
to the bell.

The resistor puts a known resistance across the line even if there are
no phones plugged in. It enables BT to detect a line break during line
testing.

More importantly, can I do without them?

Not advisably.

Yes, you can.

I hardwired a PABX into three incoming phone lines - its standard practice
to bring lines into a Krone box and punch down on analogue PABX's

Whether the PABX persenst a standrad load to teh kline that BT use in
testing or not I cannot say.

The PABX regenerates the ring current via 'master sockets' on all its
extensions. Thse have the capacitor and resistor, but not the surge
arrestor.

These are sold as PABX master sockets.

In structured wiring we don't use master sockets as such, because they are
all RJ45...the mastering is done in the dongle that adapts the BT plug on
the phone to the RJ45 socket.





I am thinking of connecting a telephone to a telephone line directly,
without a socket and the corresponding plug. This way I avoid the
socket which is visually intrusive in my particular location. I do not
mind having a fixed cable sticking out of the wall.

Move (or get BT to move) the socket.


Not necessary.

Just extend the incoming two pair to where you want to go, and refit the
master socket. I recommend crimping and burying in the wall. However be
aware that you are tending that part of the circuit that BT maintains, and
they may charge you a huge fee for fixing it if you cock it up.

Strictly you should not do this, or the entire wrath of BT's nanny state
will fall on your head. In practice no one gives a ****..but you WILL need
a mastering device of some sort to get the phone to actually ring...and the
surge arrestor may just save your phone in a lightining strike situation.

Owain