BT Wall Module - PSTN/PABX??

I'm looking at changing a BT socket on a wall to a modular style one (to fit next to an RJ45 in the same plate) and have found some on ebay, however they look identical but one is listed as PSTN and the other PABX. The only info I can find is that one is public one is private, but no idea how that helps us!

This socket currently is a very old-style, typical BT socket you'd find installed in your house about 15 years ago, so nothing fancy. It has a digital phone connected to it on our own internal phone network (not IP or anything like that)! I don't want to get the wrong type of module!

Maybe someone could advise which one we need?

PABX then - private branch exchnage
PSTN - is a normal external line

Quote:

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Originally Posted by jamesreedersmith

PSTN - is a normal external line

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'Public Switched Telephone Network'.

This isn't a master socket you're changing, is it? That belongs to BT and it's a criminal offence to interfere with it or any of the cabling up to the demarcation point.

No no, it's in an office! It's just a simple office extention which routes through to the main switchboard, with an RJ45 next to it for the office computer. I wouldn't dream of touching the master socket - not that daft! :p

So i'll need to get a PABX one then? I don't know what the difference is, as I thought a BT socket was just that, all the same! They all wire the same anyway..

Quote:

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Originally Posted by powdarrmonkey

'Public Switched Telephone Network'.

This isn't a master socket you're changing, is it? That belongs to BT and it's a criminal offence to interfere with it or any of the cabling up to the demarcation point.

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that's not true anymore the demarcation point is now typically where the BT cable enters your property, if BT change a master socket in your property for a new one then it belongs to them for 12 months and you cannot interfere with it but after that it's your problem.

Ben

STRUCTURED WIRING - RJ45 - BALUM - POT ADAPTOR - CAT5

Your internal phone system will use more of the cable pairs - PSTN only uses the two wires where the PABX may use all of them.

Well, this particular extension has the blue pairs (obviously) and the orange pairs connected (and only works with both pairs connected), but I still don't know which of the two we need!
Sounds like we should be using PABX but I don't know if getting PSTN one would make any difference or cause it not to work..

Get the PABX if it's the same price - the connectors should be the same so not sure why they're sold seperately unless the PSTN one only has two pins inside.