This topic

Master Socket 5c

chrisjp — Sun, 02 Nov 2025 20:26:20 GMT

As part of the BT Technician's investigationsfollowing my reduction in broadband speed following an outside pole replacement, he replaced my old (probably fitted around 1985) master socket with a 5c version, and reconnected my internal extension cable that runs to the extension socket into which my SH2 is plugged.

All has been reasonably well until I plugged a BT telephone plug into the Master Socket socket - this immediately cut the connection to my extension cable and my SH2 started flashing purple.

Is that normal behaviour for a 5c master socket? I can't imagine it is, because it means you can't have both an extension cable and the Master Socket socket in use at the same time

Re: Master Socket 5c

imjolly — Sun, 02 Nov 2025 20:31:14 GMT

Have you tried using old style filter in your extension as the data extension from 5c master is unfiltered

Re: Master Socket 5c

WSH — Sun, 02 Nov 2025 20:51:55 GMT

Also, if you remove the lower faceplate and plug into the test socket behind it, it disconnects any extensions.

Re: Master Socket 5c

licquorice — Wed, 05 Nov 2025 12:51:13 GMT

I suspect the socket has been wired incorrectly. The extension for the hub should be connected to the data extension terminals.