Telecom line wiring - master and slave sockets

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raytaylor

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#61113 10-May-2010 00:41

hi all

Does a master and slave telephone jack matter anymore?

I have never seen a wiring layout like the flats we currently have. A few years back we disconnected all the phone plugs and wired up a pabx system. Now i am wanting to switch it to voip and my question is about telecom telephone wiring.

Basically, can I wire my voip ATA into the back of a slave socket and disconnect the line to the road in the demarc box?

I remember being told that you dont get ringing on slave telephone jacks if you dont have a master in line first, but am wondering if this has something to do with older 3-wire systems where the master acted as more of a converter, and the capacitor circutry took the 3rd wire's voltage and added it into the 2wire system for common 2 wire telephones to use?

I do know that the demarc box on the side of the house has some circutry inside that looks like it is similar to a master socket without a plug- but this circutry is not connected to the auctual wiring.

Ray Taylor

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sbiddle

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#328350 10-May-2010 08:05

Bit of a mess but it should work fine.

The old 3 wire system was mainly to act as an anti tinkle when decadic dialling was used. In an ideal world all sockets should be 2 wire but since you're only using it for voice and not ADSL it should work fine.

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Bung

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#328362 10-May-2010 08:27

raytaylor: hi all
I remember being told that you dont get ringing on slave telephone jacks if you dont have a master in line first, but am wondering if this has something to do with older 3-wire systems where the master acted as more of a converter, and the capacitor circutry took the 3rd wire's voltage and added it into the 2wire system for common 2 wire telephones to use?

As Steve says

For completeness, the capacitor or capacitors (early 2 wire jacks) connect to the 3rd wire for 3 wire phones. 2 wire phones have their own internal capacitor and only need connection to the 2 line wires. Master and secondary jacks while OK in the UK were always subject to corrosion in NZ "leaky" homes. In 2010 don't expect them to be in top condition. The ATA ringing voltage is likely to be lower and less likely to show up low insulation between pairs.

raytaylor

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#328613 10-May-2010 17:23

Awesome.
I will just replace the masters that i come across with slaves,

Thanks again

Ray Taylor

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Bung

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#328633 10-May-2010 17:52

raytaylor: Awesome.
I will just replace the masters that i come across with slaves,

Thanks again

Unless you're putting in new jacks there's no point in swapping masters with anything just disconnect the 3rd wire.