Communication Wire

[David Dunlop]

A question for you, since I do not recall ever seeing a reel at any time with this wire on it. I think during the war it might have been referred to as 'D3 Twisted' or something like that.

What I am wondering about is if the two strands of wire are virtually identical in appearance, or does one of the strands have a trace on it of some sort? Connections on equipment seem to refer to Lines 1 and 2, or Line and Control, which suggests some sort of specific connection is needed, so I am thinking if both strands are identical, how would you remember which was which from one end of your line run to the other?


David

[Robert Bergeron]

Thank-you David,

Does anyone know what the abbreviations for line and control are ?

Could it be L and Col ?

If so , i think we just resolved a mystery in the Restoration Forum about outside connections in the Wire-5 box.

[Jon Skagfeld]

Originally Posted by David Dunlop

A question for you, since I do not recall ever seeing a reel at any time with this wire on it. I think during the war it might have been referred to as 'D3 Twisted' or something like that.

What I am wondering about is if the two strands of wire are virtually identical in appearance, or does one of the strands have a trace on it of some sort? Connections on equipment seem to refer to Lines 1 and 2, or Line and Control, which suggests some sort of specific connection is needed, so I am thinking if both strands are identical, how would you remember which was which from one end of your line run to the other?


David

IIRC, Don 3 twisted was coloured yellow and blue. Don't recall what colour the polarity might refer to.

[Robert Bergeron]

David /Jon,

Are these the wires you are referring to ?

Then, in the Wire -5 box that outlet under the Cypher clerk table would be for telephone wire and communication to/from the Box on telephone lines instead of an outside 12 VDC power source..

What do you thinks gents ?

[Jon Skagfeld]

Originally Posted by Robert Bergeron

David /Jon,

Are these the wires you are referring to ?

Then, in the Wire -5 box that outlet under the Cypher clerk table would be for telephone wire and communication to/from the Box on telephone lines instead of an outside 12 VDC power source..

What do you thinks gents ?

Sorry, senior's moment re Don 3. It was Don 8 to which I referred.

Robert: That cable inside the box looks like WD-1/TT, otherwise, sorry, can't help.

[Robert Bergeron]

No prob Jon.

The quest for an answer is ongoing.

It is fun . It's all about the chase.

Canadian military history is a blast.

[Chris Suslowicz]

Okay, Field Telephone Cables, a quick reference.

D.2 Mark IV - One tinned copper (30 SWG) and 7 hard tinned steel (34 SWG) strands, vulcanised rubber, braided cotton, black preservative compound. Weight 33lb./mile. Resistance 270 Ohms/mile. Obsolescent (1938)

D.2 Mark IV, twisted - two cables D.2 Mark IV, twisted together with a right hand lay of 12 inches. Each cable coloured blue, green or yellow.

D.2 Mark V - Strands as D.2 Mark V, insulation is pure rubber, cotton tape, braided cotton, black preservative compound.

D.2 Mark V twisted - as D.2 Mark IV twisted but with D.2 Mark IV* cable. Same colours used.

D.3 Mark VI - One tinned copper (28 SWG) and hard tinned steel (30 SWG) strands, vulcanised rubber, braided flax, red preservative compound. Weight 44lb./mile. Resistance 136 Ohms/mile.

D.3 Mark VI, twisted - two cables D.3 Mark VI, twisted together with a right hand lay of 12 inches. Each cable coloured light or dark red. Weight 88lb./mile.

D.8 Mark II - One tinned copper (28 SWG) and seven hard tinned steel (28 SWG) strands, vulcanised rubber, braided flax, black preservative compound. Weight 74lb./mile. Resistance 100 Ohms/mile.

D.8 Mark I, twisted - two cables D.8, twisted together with a right hand lay of 12 inches. Each cable coloured blue, green or yellow. Weight 148lb./mile.

D3 is normally issued to artillery units and if laid with care is almost as good as D.8; D.2 is used for temporary lines on account of portability but its resistance is high and insulation weak. For the latter reason ist must never be buried or laid in mud or water. All D.2 cables are obsolescent. (Notes on Electricity 1938.)

Telephone cables were not polarity marked because it didn't matter which way round they were connected. Some pairs did have different coloured insulation but that was more to aid identification than anything else.

If anyone wants the (nearly) complete list of field cables (from D.1 to D.10, plus the two Assault Cables and the various Quads), I mught be persuaded to compile a list.

Chris.

[Chris Suslowicz]

Originally Posted by Robert Bergeron

Thank-you David,

Does anyone know what the abbreviations for line and control are ?

Could it be L and Col ?

If so , i think we just resolved a mystery in the Restoration Forum about outside connections in the Wire-5 box.

Er, If those are for the WS19 remote control units then it's two separate pairs (as far as I know) on three terminals. One pair (Exchange Line) is used if you need to connect it to a switchboard for normal telephony use, and you cannot control the set over that (because there may well be capacitors in the way that will block the DC path for the relay and the circuit resistance will also be variable/unknown). The other pair (Control) is used between two control units (only), to operate the set from a remote position (Max 3 miles, I think, more if you add extra batteries for the DC signalling voltage to overcome the extra circuit resistance.)

The exchange line is usually connected to the "Local" control unit.

You may see earlier field telephones with three terminals (marked L, CL and E), but the CL means "Capacitor to Line" and was intended for "piggybacking" a telephone onto a DC telegraph circuit (usually railway lines) to avoid the need to lay lots of cable, especially in remote areas in India, etc. The capacitor blocks the telegraph DC circuit and the telegraph sounder is unaffected by audio frequencies (speech and buzzer calling).

Chris.

[Robert Bergeron]

Thanks Chris, most informative.

[David Dunlop]

Thanks for taking the time to document this wire for us. Much appreciated. If you get a chance, take a look at our thread in the Restoration Forum on 15-CWT, 2K1, WIRE 5 Body Details. In it, you will find some notes regarding a passthrough set of terminals on this body that look robust enough to serve several functions as a possible grounding point for the vehicle when a shorting bar is in place, or as a possible connection for 12-volt feed or as a connection for the Remote Control Unit land lines for the 19-Set. Any commits you can share there would be greatly appreciated.

Cheers for now,


David

Addendum: Well bugger me! Just noticed you have already done that, Chris. Thanks.

[Chris Suslowicz]

I aim to please (so DUCK!).

Chris.
(About to get various copies of "Notes on Electricity", "Instruction in Army Telegraphy", "Infantry Signal Training", "Signal Communications in the Army", and some just post-WW2 stuff on "future requirements" that I photographed at Kew out so that I can do a list of D1 through D10, Assault Cable No.1 and No.2, Field, Carrier and Lightweight Quad, and just possibly the 10-pair cable used with the Switchboard 40/160 Line. I may be some time)

[Ron Pier]

Sorry to but in! Chris am I getting through by email or PM? Ron