If you open up a BT telephone socket you see a few electroni
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 th socket which is visually intrusive in my particular location. I do no mind having a fixed cable sticking out of the wall.
Thanks,
Antoni
-- asalcedo
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
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.
Not advisably.
Move (or get BT to move) the socket.
Owain
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!
asalcedo wrote
No.
You could hide the master box in the loft or somewhere, and run a long lead from it to the telephone.
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.
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.
And the non-linear resistor clamps over voltage should it get across the pair (I think)?
All the best ..
T i m
Hi Tim,
Thank you for your explanation. It makes sense. I did not know that th ring is done with AC.
I have now done some additional research on the issue and understan the BT Telephone socket wiring.
The conclusion is that circuitry is not needed for my purposes, my lin does not go outside.
Thanks,
Antoni
-- asalcedo
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 :-<
Do you mean it's a PBX extension? Depending on the telephone you may still need the capacitor for ringing.
Owain
Mike Clarke wrote
Sods law strikes again.
(Haw, haw) ;-)
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.
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 c*ck 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 f*ck..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.
Yebbut, but that's a PBX which is permanently connected.
It's a sufficient load on the line that BT can check that the line hasn't gone o/c
Yes, not needed on internal extensions.
But somehow I didn't think the OP was running a roomful of Strowger :-)
Owain
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