Need cable advice - UK Vintage Radio Repair and Restoration Discussion Forum

oldphoney · 18th Oct 2014, 6:05 am

One phone I'm working on has a ridiculously short cable which I'll need to replace. Several things confuse me so this is a two-part question.

1. Screw terminals implies thick wires?
In order to connect to the screw terminals, I'm thinking I need cable with wires that are thicker than the wires used for RJ-11 and Cat 5. But where can that kind of wire be found these days, and in a nice cream colour?
Another option might be to use some gel connectors a sparkie friend left me some time ago (3M "Scotchlok UR"): using modern cable from the plug to the gel connector, then splice a tail from the gel connector to the screw terminals.
Any input appreciated!

2. RJ11 connection with thick wires?
Apparently this Ericsson phone was used by the French PTT, and it came with a French plug. I tried to eliminate the French plug and crimp the original cable into an RJ-11, but after many tries I couldn't get the plug to work. Pushing the copper as far back as it will go — no luck.
So to test the phone I resorted to the hack in the picture: the phone is wired into a French-plug-to-RJ-11 adapter. It's ugly and I'm sure I can drill into the plug to tidy it up, but there must be a better way.

Thanks in advance for your thoughts

ThePillenwerfer · 18th Oct 2014, 9:27 am

Option 1 above would certainly work but the best thing is to solder tags to the ends of the modern thin wire to go on the 'phones terminals.

- Joe

julie_m · 18th Oct 2014, 1:13 pm

It's certainly possible for the cable to be too thick to fit an RJ-11 plug. If the insulation on the inner cores is sufficiently thin to allow them through the individual contact channels, you might get away with removing enough of the outer sheathing to clear the plug body altogether; but then of course you will have no strain relief.

Depending how visible the socket and cable are going to be, you might be better off opting for an inline splice to a suitable RJ-11 cable and plug. Or you could replace the cable altogether.

Also, just an observation: That French connector looks like a pass-through adaptor; if it is to become a permanent fixture, it would be neater to bring the cable out from the bottom. And if it was really a three-wire phone, it will be able to make and answer calls but will not ring out on an incoming call (the French system, like the BT system, relied on an external capacitor to separate the AC ringing and DC speech circuits).

mike_newcomb · 18th Oct 2014, 1:22 pm

Hi Oldphoney,

How long do you require the cable and with how many wires?

Here in the UK, various length, modern type cables are available with an RJ11 plug one end, and terminals already crimped on the 2 or 4 wires on the other end for screw terminals. Check the online auctions for such. Generally colour is white though.

Furthermore, I suspect for the wires, carbon ribbon instead of metal is used, giving cable greater flexibility, thus cannot be soldered. only crimped

Prior to RJ11, the round cable used by BT, feeding (sometimes only 2 wire) and within private properties, was 4 wire, each a thickish single strand, as then, terminal blocks had screw connections.

Regards - Mike

18th Oct 2014, 1:56 pm

The old trick for tinsel wire was to wrap it in thin tinned copper wire. It will also work for beefing up thin wires. A quick binding with cotton will add a strain relief too.

dagskarlsen · 18th Oct 2014, 1:58 pm

Spade terminals like these http://tinyurl.com/nvumhp6 are working well on those soft flat cables, they are not easy to solder.

The Scotchlock solution will just work fine.

dsk

oldphoney · 18th Oct 2014, 7:30 pm

Wow, so many neat ideas! Thanks, everyone.

- hadn't considered an inline splice. I may have a tiny junction box somewhere that would work well
- if replacing the cable, I have some fork terminals (you call them tags / spade terminals?) in a dark corner of the workshop so that idea will work
- will look at the cable replacement option on the auctions
- neat to know the copper + cotton trick. This time if splicing I'll try the Scotchlok connectors first

@mike_newcomb about your questions: here in NZ only needing 2 wires inside the cable. For length, thinking somewhere around 2 meters—easy enough to extend. The standard phone outlet/plug here is called a "BT plug", presumably from the British Isles and the same as yours. RJ-11 adapters are common and that's what I'm looking to use.

Really excited about these phones, many thanks.

Wishing you all a fun weekend

OscarFoxtrot · 18th Oct 2014, 8:48 pm

RS (RadioSpares) used to to a BT plug which had screw terminals and, I think, accepted a 'square grommet' UK telephone cable.

Oldcodger · 18th Oct 2014, 11:43 pm

Quote:

Originally Posted by merlinmaxwell

The old trick for tinsel wire was to wrap it in thin tinned copper wire. It will also work for beefing up thin wires. A quick binding with cotton will add a strain relief too.

Another old trick was to strip back a bit of insulation on the wire, leaving the tinsel and fabric. Twist the plastic n the end, solder with abit of flux, and

oldphoney · 19th Oct 2014, 8:54 pm

Hi everyone,
Thanks for the continuous flow of tips.
Reporting back on yesterday's efforts.

- The Scotchlok UR didn't work for me. I tried four times (eight plugs) and didn't get a dial tone. They say not to strip the wire, so I didn't. I was splicing the old wire with some modern thin RJ-11 wire, and wondered if either the insulation was too thick on the old wire (they say not to strip it), or if maybe the connector cut right through the thinner. On one of the attempts I stripped the thicker wire. Later I tested two connectors I had cut off a bit long with a voltmeter: one had worked, the other not.

- I ended up soldering the thin wire to fork connectors. It worked but what a mess. First I'm terrible at soldering. No matter how many of these videos that make it look easy I watch, it never works that way for me. Maybe the solder is the wrong kind. Second, I found it really hard to solder these tiny wires from modern phone cable, because they're very hard to strip. I thought there's no need to strip them, but wasn't successful until they were bare.

After all this, it turns out that the phone works in the one plug near which I was working, but not in the other plugs in the house. The plugs must be wired strange: some of my phones work in some plugs, some work in others. One day soon I'll have to open a plug and take a look!

Wishing you all a great week.

18th Oct 2014, 6:05 am	#1
oldphoney Retired Dormant Member Join Date: Sep 2014 Location: Wellington, New Zealand Posts: 13	Need cable advice One phone I'm working on has a ridiculously short cable which I'll need to replace. Several things confuse me so this is a two-part question. 1. Screw terminals implies thick wires? In order to connect to the screw terminals, I'm thinking I need cable with wires that are thicker than the wires used for RJ-11 and Cat 5. But where can that kind of wire be found these days, and in a nice cream colour? Another option might be to use some gel connectors a sparkie friend left me some time ago (3M "Scotchlok UR"): using modern cable from the plug to the gel connector, then splice a tail from the gel connector to the screw terminals. Any input appreciated! 2. RJ11 connection with thick wires? Apparently this Ericsson phone was used by the French PTT, and it came with a French plug. I tried to eliminate the French plug and crimp the original cable into an RJ-11, but after many tries I couldn't get the plug to work. Pushing the copper as far back as it will go — no luck. So to test the phone I resorted to the hack in the picture: the phone is wired into a French-plug-to-RJ-11 adapter. It's ugly and I'm sure I can drill into the plug to tidy it up, but there must be a better way. Thanks in advance for your thoughts Attached Thumbnails Last edited by oldphoney; 18th Oct 2014 at 6:16 am.

18th Oct 2014, 9:27 am	#2
ThePillenwerfer Octode Join Date: Mar 2011 Location: Sheffield, South Yorkshire, UK. Posts: 1,453	Re: Need cable advice Option 1 above would certainly work but the best thing is to solder tags to the ends of the modern thin wire to go on the 'phones terminals. - Joe __________________ "Experts are only good at one thing: explaining why something will not work!"

18th Oct 2014, 1:13 pm	#3
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Need cable advice It's certainly possible for the cable to be too thick to fit an RJ-11 plug. If the insulation on the inner cores is sufficiently thin to allow them through the individual contact channels, you might get away with removing enough of the outer sheathing to clear the plug body altogether; but then of course you will have no strain relief. Depending how visible the socket and cable are going to be, you might be better off opting for an inline splice to a suitable RJ-11 cable and plug. Or you could replace the cable altogether. Also, just an observation: That French connector looks like a pass-through adaptor; if it is to become a permanent fixture, it would be neater to bring the cable out from the bottom. And if it was really a three-wire phone, it will be able to make and answer calls but will not ring out on an incoming call (the French system, like the BT system, relied on an external capacitor to separate the AC ringing and DC speech circuits). __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

18th Oct 2014, 1:22 pm	#4
mike_newcomb Rest in Peace Join Date: Apr 2012 Location: West London, UK. Posts: 665	Re: Need cable advice Hi Oldphoney, How long do you require the cable and with how many wires? Here in the UK, various length, modern type cables are available with an RJ11 plug one end, and terminals already crimped on the 2 or 4 wires on the other end for screw terminals. Check the online auctions for such. Generally colour is white though. Furthermore, I suspect for the wires, carbon ribbon instead of metal is used, giving cable greater flexibility, thus cannot be soldered. only crimped Prior to RJ11, the round cable used by BT, feeding (sometimes only 2 wire) and within private properties, was 4 wire, each a thickish single strand, as then, terminal blocks had screw connections. Regards - Mike

18th Oct 2014, 1:56 pm	#5
Guest Guest Posts: n/a	Re: Need cable advice The old trick for tinsel wire was to wrap it in thin tinned copper wire. It will also work for beefing up thin wires. A quick binding with cotton will add a strain relief too.

18th Oct 2014, 1:58 pm	#6
dagskarlsen Heptode Join Date: Jan 2008 Location: Hakadal, Norway Posts: 642	Re: Need cable advice Spade terminals like these http://tinyurl.com/nvumhp6 are working well on those soft flat cables, they are not easy to solder. The Scotchlock solution will just work fine. dsk

18th Oct 2014, 7:30 pm	#7
oldphoney Retired Dormant Member Join Date: Sep 2014 Location: Wellington, New Zealand Posts: 13	Re: Need cable advice Wow, so many neat ideas! Thanks, everyone. - hadn't considered an inline splice. I may have a tiny junction box somewhere that would work well - if replacing the cable, I have some fork terminals (you call them tags / spade terminals?) in a dark corner of the workshop so that idea will work - will look at the cable replacement option on the auctions - neat to know the copper + cotton trick. This time if splicing I'll try the Scotchlok connectors first @mike_newcomb about your questions: here in NZ only needing 2 wires inside the cable. For length, thinking somewhere around 2 meters—easy enough to extend. The standard phone outlet/plug here is called a "BT plug", presumably from the British Isles and the same as yours. RJ-11 adapters are common and that's what I'm looking to use. Really excited about these phones, many thanks. Wishing you all a fun weekend

18th Oct 2014, 8:48 pm	#8
OscarFoxtrot Heptode Join Date: Apr 2011 Location: Edinburgh, UK. Posts: 805	Re: Need cable advice RS (RadioSpares) used to to a BT plug which had screw terminals and, I think, accepted a 'square grommet' UK telephone cable.

19th Oct 2014, 8:54 pm	#10
oldphoney Retired Dormant Member Join Date: Sep 2014 Location: Wellington, New Zealand Posts: 13	Re: Need cable advice Hi everyone, Thanks for the continuous flow of tips. Reporting back on yesterday's efforts. - The Scotchlok UR didn't work for me. I tried four times (eight plugs) and didn't get a dial tone. They say not to strip the wire, so I didn't. I was splicing the old wire with some modern thin RJ-11 wire, and wondered if either the insulation was too thick on the old wire (they say not to strip it), or if maybe the connector cut right through the thinner. On one of the attempts I stripped the thicker wire. Later I tested two connectors I had cut off a bit long with a voltmeter: one had worked, the other not. - I ended up soldering the thin wire to fork connectors. It worked but what a mess. First I'm terrible at soldering. No matter how many of these videos that make it look easy I watch, it never works that way for me. Maybe the solder is the wrong kind. Second, I found it really hard to solder these tiny wires from modern phone cable, because they're very hard to strip. I thought there's no need to strip them, but wasn't successful until they were bare. After all this, it turns out that the phone works in the one plug near which I was working, but not in the other plugs in the house. The plugs must be wired strange: some of my phones work in some plugs, some work in others. One day soon I'll have to open a plug and take a look! Wishing you all a great week.