Question about telephone wiring

[Davidm]

I've recently installed a trueCall Call Blocker, and have had some problems with it not ringing when it should. Turned out a wired phone wasn't ringing when I plugged that in to test things. Virgin Media came out and run some tests at their Junction Box on the wall of my house (JB1), and found a cable fault between their street JB and one further away. They fixed that and the phone works ok now, but the trueCall box still isn't behaving itself. The trueCall box is connected to an extension socket (see below), then the cordless phone basestation connects to it.

I've investigated the house telephone wiring, which has had quite a few "unofficial" phone extension boxes added over the years but there's one very odd thing:

From JB1 a cable runs through the house wall to the lounge and to a master phone socket (2 wires to the A&B terminals). From the extension connector in that socket another cable (Cable A) goes back to JB1 (1-blue/white, 3-orange, 5-white/blue). When I had VM broadband installed I asked for a telephone extension to be added in the 2nd floor study, together with the cable modem. So in JB1 there's a VM installed black cable (Cable B) going up to the second floor but only the blue/white and white/blue from Cable A are connected to Cable B, the orange wire is just floating. In the study Cable B is connected to a second master phone socket, the two wires going to the A&B terminals. All of the house phone extension sockets are then daisy chained from the second master socket.

So effectively I have two master phone sockets in series, is this likely to cause any problems?

[Dave Plowman (News)]

Older wired phones may require 3 wires to ring. Things like a base station for cordless, only two. Assuming your socket is correctly wired, TrueCall will work with either.

I've got a variety of phones installed here - from before the days of cordless. So all the sockets wired for three wire types. And only one master socket.

Snag I found with TrueCall plugged into only one phone, was some of the others could ring briefly before TC intercepted the call.

So I had to do some re-wiring to have it where I wanted it, but fitted on the incoming line before all of the phones.

Here are the standard colours of cable, flex and their terminals.

Terminal Cable Cord Function 1 Green/white Orange Spare Blue 2 Blue/white Red B wire (Line) -50v Brown 3 Orange/white Blue Shunt wire. (Bell) Green 4 White/orange Green Local earth (Not usually used) Orange 5 White/blue White A wire (Line) 0v 6 White/green Black Spare

[Mike Humphrey]

It's not a correct installation, and might cause some issues with fault reporting - though if VM installed it like that you're on solid ground with getting them to fix it. Having said that, it should work fine. Have you tried unhooking all the extensions and plugging direct into one of the master sockets?

Mike

[Davidm]

@Dave & Mike Thanks, helpful information. For the moment I've disconnected the two wires in Cable B from the second master socket (and insulated them - they're indoors so no moisture risk), so that the only thing now connected is the first master socket, and I'll run the trueCall from that and see if it helps. With 4 cordless phones around the house I probably don't need all those wired extensions anyway. It's been an interesting learning exercise :) I also had an Orchid dialler connected, but have removed this for the moment. That really needs to sit between the master socket and the trueCall box, to handle routing of outgoing calls, but one thing at a time!

[Brian Gaff]

Yes I have a truecall unit and am on Virgin. I chopped off the second master and used a plug in lead to make the connection to the other rooms and it works. Another little wheeze I learned of is to add a phone just before the truecall, so I know when idiots ring once and put the phone down and can use it to see if a number is revealed. Can be handy when idiots at nhs ring up and think its an answerphone and put the phone down.

Brian

[Brian Gaff]

Well, I would advise you to have at least one old fashioned line powered phone on the truecall for when you get a power cut. truecall defaults to straight through, so this should work fine. Brian

[Harry Bloomfield]

Brian Gaff brought next idea :

Good advice to have an ordinary phone, for emergencies and power cuts - I have one, but with the ringer turned off.

Idea of the Truecall is to filter the calls, not let them straight through unfiltered - letting just the calls through you want. If the Truecall is built into the wireless phones, then calls would still get through to the ordinary phone and cause it to ring, unless the ringer is turned off.

[Dave Plowman (News)]

Yes it does. I fitted a switch in its DC power supply to disable it when expecting a call it would block - like say from a hospital switchboard. Quicker than doing it with their software.

[Davidm]

Yes I have, it's not normally connected, but nearby in a drawer with a torch. Plus of course we have mobiles.

[Harry Bloomfield]

on 22/07/2019, Dave Plowman (News) supposed :

Does the hospital switchboard not present a number that you could whitelist?

[Dave Plowman (News)]

I've got the main one listed. But they may have outgoing lines which appear as a different number to it.

[Dave Liquorice]

truecall

Mobile phone cell sites require mains, very few sites have battery backup beyond a few hours, if that. Almost none have generators. Expecting the mobile phone network(s) to work under power fail conditions is a bit risky.

[Andrew]

If they have set up their hospital switchboard correctly, then even the direct-inward-dialling numbers should only show the main switchboard number on caller-id, and not the actual number of that extension.

[Andrew]

You should ring this number every so often to make sure ~60 volts stops any high-resistance joints occurring (assuming this is a broadband-only line).

[Roger Hayter]

That is one way to set it up, but not necessarily the"correct" one. If an individual or a department with a receptionist, or only one outside phone wants to they should be able to set up their own number for presentation, so they can deal with their own calls.

[Dave Plowman (News)]

Fact remains that I have the official hospital number on the list, but calls from it get blocked.