[TheList] Phone Jacks

Mon Oct 29 14:56:49 AEDT 2012

This is a simplistic description, but should help you understand how it
works. As you will know, there are two wires from the exchange. In the early
systems there would be a 'master' outlet which had a capacitor, and usually
a test resistor and lightening arrestor. Typically this outlet would have a
'M' on the front somewhere. This 'master' outlet separated the ring signal
from the line and sent it to any connected phones using a third wire
(usually blue). All other outlets had the same PCB inside but the components
were not installed. These were called 'Secondary' outlets and had an 'S' on
the front.  This system was known as the 'three wire' system. Following
this, they moved to a system where each outlet had its own capacitor and the
ring signal was separated out at each outlet. This was called the '2 wire'
system and the outlets had a '2' on the front. Nowadays, most phones have
their own capacitor or other circuitry built in to handle the ring signals.
The simple way to tell this is if the phone only has two wires in its line
cord. Because of this you may not need a capacitor in any outlets, and so
any type will do. Hope this helps.

Mark.

From: TheList [mailto:thelist-bounces at radiowiki.org.nz] On Behalf Of John
Barnhill
Sent: Monday, 29 October 2012 3:40 p.m.
To: thelist at radiowiki.org.nz
Subject: [TheList] Phone Jacks

I am needing to replace my 'master jack' which has gone faulty (phone rings
but no voice/line noise) - it is a 'Saturn' jack and has a 105K250JS
capacitor inside it. The 3 extension 'jacks' that are fed from this 'master'
are all working OK. Once I mention the 'capacitor' to DSE, Jaycar, Egleys
etc. they all go into 'don't know mode'. As I don't have a 'line maintenance
contract' with Telstra Clear (who took over Saturn) they want $300 to have a
look at it. What 'phone jack' should I be asking for?

Thanks,

John B

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://radiowiki.org.nz/pipermail/thelist_radiowiki.org.nz/attachments/20121029/04eceaee/attachment.html>