A Quirk of Eircom wiring to watch out for!

Solair

I was just doing a little bit of re-routing of telephone wiring in my house and just noticed something that might be worth looking out for if anyone's considering tackling their phone installation.

There is a type of eircom socket which dates from the late 1990s. It's a version that was used between the older beige siemens sockets that we're all familiar with (the ones with the single screw on the front) and the current NTU with the removable face plate and optional DSL face plate etc.

This socket is white and has has two screws on the front near the bottom which reveal terminals marked L1, R and L2 where the end user can connect extension wiring to L1/L2 (or an old 3-wire hardwired bell telephone to all 3 terminals)

The weird quirck which I discovered by accident is that there's a magnetic interlock switch in the socket!!

The cover contains a little magnet and there's a switch in the socket. When the cover's removed, the L1 and L2 terminals are disconnected from the line. When it's replaced they're re-activated again.

I couldn't figure out why the terminals were dead when I connected up my extension wiring to L1 and L2! Then noticed a little block on the cover plate and it suddenly dawned on me what was going on!

I assume this set up is designed to prevent the customer from coming into direct contact with live line voltages when doing DIY wiring and also makes it very easy for an eircom technican to check the line i.e. remove the panel and the extension wiring should be disconnected.

The modern NTU achieves this as the face plate plugs into the socket providing the line, so once it's removed, the extension wiring's also dead.

Strange system though... just thought I would let you know as it's a bit baffling if you don't realise what's going on!

FusionNet

Ya this was a nightmare when it came out first and caused a lot of problems!! Whats worse is there are a lot of them out there! Good job for figuring it out though...

Solair

I'd say plenty of people simply assume the terminals don't work.
I have to say, from a decor point of view, the original beige Siemens sockets were a far neater job. I don't like this big bulky white yokes! I don't understand why they stick out so far from the wall. Surely they could make a flush-mount version!?

FusionNet

the reason there so bulky is because they are the master socket and all other lines need to be fed into them. All the other sockets in a house can be tiny but you are better off leaving the original Eircom one, Eircom engineers get annoyed if you remove it!!!