WWII MILITARY FIELD TELEPHONE TYPE "J"

One of a range of field telephones made during the Second World War and used by the Army. Similar to type 'L' see item A1681. An extra earpiece facility is provided with connection to two terminals on the left. A pull switch marked 'KEY' in the front of the battery compartment is for calling using a Central battery. A GPO Magneto when turned using the handle on the right sends an AC voltage to the receiving station and rings the bell.Two terminals on the right are marked 'L1 and 'L2' which are connected to the line to the other unit, if L2 is connected to the ground then only one wire is needed for the line These sets were made by manufacturers officially approved by the General Post Office (GPO), and are not always marked by the maker.

Your comments:

• There is more to D10 than mentioned below, as compared to the previous D3 /D8 cables.
  
  D10 is double plastic covered twin wire and has a twist built into it so it stays well inside a 1/2mile cable pack capable of being carried on a persons back. (previously all cable was single wire kept on drums)
  It has 7 strands - four steel for strength and 3 copper to give good conductivity.
  I special jointing tool was also developed by Hellerman of Crawley in Sussex, used with copper joints in place of the former self soldering joints or hand made reef knot joints.
  I am not sure when it came into service, but I think the late '50's, in the 70's there was a proposal, more from a camouflage perspective than from any other to have black and green twisted wires, but this never seems to have been adopted.
  Mike
  .......... Mike Buckley, Croydon, 17th of November 2013
  
  
• Good Evening Guys,
  I worked with some of these which must have been a later mark,(circa 1960s and 1970s) as we called them Tele "L". As you say, joined by telephone wire, which by then was Don 10 (two more strands in the cable) Two 1.5 dry cells went in the box at the back. You could use them on radio nets in radio relay mode, using line equipment known as 1 plus 4 pn C41/R222 links or, using a J box, on a C11/R222 station. (Meant the set was in the rain soaked Land Rover and you were in the dry German barn!!!)They were great for testing cartridge fuses, by shorting the two knurled terminals out with the fuse under test, and cranking the handle. A good ring meant a good fuse, and , as stated, o good shock for the careless!! Electricity bites fools!!! If you knew how, you could tap a Don 10 line with them and a specially rigged terminal block, or, if you did not mind ruining the terminal block on this one, on the Tele L itself.Hours of endless fun!!! It's big brother was the Tele "F", which, if memory serves, was bigger, and had two large bells on the back, and a crank handle at the front. It was for use in more permanent locations, I think. Happy days! Gary H.Old Scaley (Signaller)
  .......... Gary, Cardiff UK, 20th of October 2013
  
  
• This model was also used by Civil Defence until its disbandment in 1968.
  Two different types of cell were used, an ordinary dry cell, and another type which required the addition of water to activate it. I never actually saw this latter type in use.
  These field telephones were used with "Don-8" cable which comprised seven strands of steel and one of copper, insulated and covered with cloth. The cable was provided as a twisted pair. Cable could be laid in one of three ways (from a back-pack, from an A-frame carrier on the back of a Land Rover, or by two men using the same A-frame but folded flat like a stretcher). The drum for the back pack contained a smaller amount of cable. Our Land Rovers carried a number of wooden poles that could be fitted together like old fashioned tent poles to support the cable. A device called a crook-stick for laying cable over obstacles like hedges, and simple testgear and tools.
  We also had available switchboards.
  One of the first training involved learning how to test a Tele "J". Voice testing was easy, you just blew into the microphone and listened for "sidetone". Testing batteries was done with a simple meter. Testing the magneto generator could be done in one of 2 ways. The official version was to crank the handle with the line terminals open circuit, then again with a short circuit, in the shorted condition it was markedly more difficult to turn. The unofficial version was to place 2 fingers on the line terminal and turn the handle, when you would feel a shock (in normal use the output was about 75-85volts AC, but when open circuit it was quite a bit more, maybe 200!). If you were training those unaware of what would happen you told them that they needed to lick their fingers!
  
  I served in Civil Defence for the last 3 years of its existence, mainly in Sigs B (The field cable section of the HQ branch).
  .......... Steve Cook, Richmond/Surrey, 21st of December 2009
  
  

A0850