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Thread ID: 49609 2004-09-25 02:14:00 Types of phone outlet sockets Andrew B (867) Press F1
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275419 2004-09-25 02:14:00 I am replacing our house phone wiring, changing from a 3 wire system to the 2 wire system. Can I use the old 3 wire system secondary socket, the ones without any components like caps attached, with the new 2 wire system? I have a couple of new 2 wire sockets and they have a light brown component, with 105k printed on it, soldered onto the circuit board. What does that thing do? Thanks. Andrew B (867)
275420 2004-09-25 02:36:00 When I did a extra phone point in my house I went through similar questions.
Dick smith had a very helpful and detailed pamphlet on the subject.

Hope this may be helpful to you.
John D (1571)
275421 2004-09-25 02:53:00 No problems there Andrew, as long as it is the secondary. The component is a 150,000 Ohm resistor. Just ignore it.

On the secondary jackpoints, use only the middle connection on each side. The 2 wire versions look the same, but the 3 connections are commoned together. So the left-hand side are all joined together, and the right hand side are all connected together. The secondary type jackpoints have each connection going to a different pin on the socket.

OK with the explanation?
Pheonix (280)
275422 2004-09-25 02:56:00 Sorry , that component mentioned is actually a capacitor, just cut it off the board.
Damn brain needs more coffee...
Pheonix (280)
275423 2004-09-25 03:21:00 There are no "Master" or "Secondary" sockets using the 2 wire system - they are all the same and should preferably be star wired, not series/parallel wired as with the old 3 wire system, though they will still work if wired in parallel. This means that effectively, they are all "master" sockets and as such, have the 1 microfarad capacitor connected - you will run into problems if you disconnect these. You should not mix and match. Either have one system or the other and use the approved equipment for the system you use. andy (473)
275424 2004-09-25 04:07:00 >should preferably be star wired, not series/parallel wired as with the old 3 wire system

why ??

from what i've been told the signal don't like star wired system, daisy chained outlets are better.
tweak'e (174)
275425 2004-09-25 04:36:00 Your sockets should not be star wired if you want to use modems on the system.

The twowire sockets should have a capacitor (1.8 microfarad, 250V) between pin 5 (I think, but maybe 2 ;-)) and 3. But if you have only modern phones (with electronic ringers) you don't need this. It's only there for "legacy" phones with real bells. There seems to have been two generations of 2-wire --- the first, with pins 1,2,3 and 3,4,5 commonned together. The later has a capacitor ... probably someone realised that there are a few million old phones with bells, which won't ring on real two-wire systems.

The important pins are 2 and 5. You could use a master socket if you have an old phone at one location.

Do a search for "PTC" ... I think it's PTC 100 which will tell you more than you want to know.
Graham L (2)
275426 2004-09-25 04:41:00 I reckon it would be the other way around tweak'e. Daisy chaining introduces multiple connections into the signal path whereas star wiring only has the terminations at each end of the cable.

HF signals don't like impedance variations along the cable length, and even at DSL frequencies standing waves are possible. Personally I would favour star wiring every time, but no doubt one of our telecom experts will put us right. I have Telecom spec for DSL 2-wire systems here somewhere, I'll see if I can find it.

Cheers

Billy 8-{)
Billy T (70)
275427 2004-09-25 04:51:00 Telecom specify daisy chaining. It's unterminated stubs caused star connections which cause some of the problems. Graham L (2)
275428 2004-09-25 04:55:00 >Telecom specify daisy chaining.

yet 99% of sparkies wire it stasystem....mmmmmmmmm
tweak'e (174)
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