telephone leads

[Roger]

Friends have a Mickey Mouse* phone that needs new leads but as usual I am confused by the wealth of goods available on the Internet.

Handset to base leads apparently come with 3 flavours of RJ terminal attached, presumably differing in size but how do I establish which size is needed?

A similar problem arises with the BT socket to base lead but this might have complications as I think the phone might be wired to an American pattern. Substituting the handset from MM on my Binatone phone gives a buzz, not a dialling tone.

So is the RJ socket in normal use on telephones RJ10 and what, precisely do I need to look out for with the BT socket to base lead.

*Yes literally a Mickey Mouse phone. This dreadful contraption is a model Mickey Mouse with the handset hanging from one arm and a fake rotating dial in the base. It squawks out a loud message whenever the phone rings and was appropriately placed close to the parrot's cage. Unfortunately (or fortunately depending on which way you look at it) too close to the parrot who has chewed through both wires. Not the sort of wires that I think I could solder together as there is material interwoven with the conductors presumably to give added strength. Application of a flame to remove insulation and interwoven material doesn't leave very much at all.

[T i m]

;-)

They generally can be soldered (certainly for test purposes) but it can be fiddely (I've done so many_a_time).

I generally strip back the external insulation 10mm or so (I often 'cut' the insulation with the soldering iron to save shredding the conductors) then separate the conductors from the other junk by hand and that point you should be able to twist then 'tin' the conductor strands together ready to solder to whatever.

Some heat shrink will often make a pretty tidy job of the whole thing (applied at the appropriate stages).

Replacement leads can be made up with suitable crimp connectors (RJ11/BT), once you know the pin out of each, easily worked out from the old cables).

All the best ..

T i m

[Roger Mills]

It's probably better to ask in uk.telecom - but I'll have a go at answering.

The cable which joins the phone to the BT phone socket usually has an RJ11 plug at the phone end. An RJ11 plug can take 6 wires, but the outermost wires are never used in this application. There are at least 3 variations of a BT to RJ11 lead. Two of these are for 2-wire connections to devices which have their own ring capacitor, and don't need a bell wire. A pair of conductors is *always* connected to 2 and 5 at the BT end. At the phone end, that pair is either connected to the innermost 2 connectors (3 and 4) or to the outer pair of the 4 used ones (2 and 5). Modems invariable use the inner pair, and I suspect that some 2-wire phones do too. For phones which need a bell wire, this will be connected to 3 at the BT end (in which case there is probably a wire connected to 4 also, even though it isn't needed). I don't know for sure, but I guess that phones which *do* need a bell wire use the outer pair at the phone end for the main connection, and 3 or 4 for the bell. Armed with this information, if you strip back the cable where it is broken, and hold each of the coloured brades together in turn, you should be able to use a continuity tester to determine what flavour you have.

On all of my phones which I have just examined, the plugs on the handset to base cables are narrower than RJ11s and cater for only 4 conductors. All of mine cross the connections over - which can be seen by holding the plugs side by side and looking at the colour of the wire connected to each metal connecting strip. This is probably universal, so the handset to base cable off any old phone (local tip, Freecycle etc.) should do.

[Chip]

On Sun, 2 Mar 2008 11:13:30 GMT,it is alleged that Roger spake thusly in uk.d-i-y:

As mentioned elsewhere in the thread, handset to base leads are usually 4c4p (sometimes known as RJ10) plugs, and usually cross over.

The exact wiring allocation in the handset cord isn't standardised, so you might have the mic feed or even one wire from the mic and one from the earpiece feed on the receiver (if you see what I mean), doesn't mean anything much :-)

They're tinsel cord, very difficult if not impossible to solder, and it won't hold even if you do, due to the soldering destroying the nylon threads that give it strength. If you can't find a replacement, crimping works well with these, probably using the barrel of a red terminal without the insulation (snip off the actual terminal). If you stagger the crimps, the overall diameter won't be much more than the original cord. If the handset cord is white, I have one I could let you have, my email address is valid, but let me know on group if you've emailed so I can go check it :-)

[Roger]

The message from Chip contains these words:

These are wired in what I would call mirror fashion. If the end connectors are butted up face to face the colours appear to continue. This is the same as the lead for my Binatone phone. Other references are to RJ11 as well which I am finding baffling.

It was the BT to base wiring that is cause for concern in addition to the exact type of BJ socket in use.

snip

You haven't seen me attempting to solder with my outsize 1950s soldering iron. :-)

Very kind of you to offer but the leads are black and in any event it wouldn't be right to put you to the trouble of supplying a lead when they are apparently readily available if only I could be sure what is needed.

While making another search for long dead telephone equipment that I was virtually certain I had thrown out (and which didn't surface) I cam across a telephone line splitter with one standard socket and 6 feet of wire wired to what I think is a BJ10 with just the inner 2 connections in use which matches the MM set-up. I presume this is intended as a modem connection.

I am pleased to be able to report that the MM phone works using this new find and the handset lead from my Binatone.

So I can now go out and buy a readily available RJ10 to RJ 10 handset lead but what precisely do I look for for the base lead?

Looking at cpc's site "COILED CBL 4P4C-4P4C BLACK 1.5M" would appear to be right for the handset (or is it the uncoiled length in which case should it be the 3M one) but I can't see any BT plug to RJ10 and the BT plug to RJ11 are all 4 core cable, not 2 core. So is the difference between RJ 11 and RJ 10 the way in which they are wired or are they a different size. If the former is "BT PLG TO RJ11 1M WHT C/WIRED" what I want? (They don't do c/wired in black).

Thanks again to Chip for his offer of a lead and thanks also to the others who have taken time to respond to this thread.

[Chip]

On Sun, 2 Mar 2008 17:15:29 GMT,it is alleged that Roger spake thusly in uk.d-i-y:

[snip]

It's good to hear you got it working :-)

I understand what you mean by the colours continuing, and yes, that's pretty much how they all are, so a standard off-the-shelf cable should work fine.

The subject of the American plug styles is a long and involved one... so if we're sitting comfortably

American phone service was formerly supplied using specified types of wiring to the jack, which were registered by the FCC, hence registered jack or RJ.

The actual plugs are supposedly just called 'modular plugs'.

The type used by modems and adsl connections is RJ12, which is also known as 2C6P meaning 2 contacts, in a shell capable of having 6 contacts. (I think this is what you have from your description, in which case a 'modem' or 'dsl' wired cord will be the one you need)

RJ14 is the same size, only with 4 contacts- 4C6P (It's often misnamed RJ12)

RJ10 isn't an official designation, but is often used for the 4C4P handset plugs which due to being 4 position are smaller than the line plugs.

8C8P connectors here are most familiar as ethernet plugs, often misnamed RJ45 (The original RJ45 was a specific type of telephone line wired for a specific type of modem, but common usage now has all ethernet plugs being called RJ45)

Also, with regard to the 1950s soldering iron, it'll probably last a lot longer than the modern ones :-)