Pattern 210X Navyphones
The Royal Navy's Pattern 2108 and Pattern 2109 Navyphones were intended for fire control purposes, being fitted in control positions and guns, respectively. The original models were battery powered, and were later followed by Pattern 2108A and Pattern 2109A which could be powered by batteries or by motor generator.
2108 and 2109
As shown in the Torpedo Drill Book, 1914, the little circle suggests each has a call-up push, but the 2108 was the only one to have this.
These two phones were probably identical in general appearance, except the 2108 (at the control position) had a push button to ring an external bell near the 2109 at the gun position and the 2109 had no call-up button. Consistent with a need to keep fire control phones entirely free of cross-talk, the phones were always wired in pairs by 4 wires with no switchboard or multiplexing. The cases were iron, and the receiver horn was probably copper and projected from beneath the case as in the Pattern 1855 Navyphone.[Inference] A momentary push-to-talk lever was located on the lower right.
The receivers were always on-line, which meant that if the "Press for speaking" button at either end were pressed, an intercom-like loudspeaker function would result. However, if the 2108's call-up button were pressed, the 2109's external bell would ring for that extra bit of attention.[1] This seems consistent to the greater noise that might be at the guns and also reflects the one-to-many relationship of a control position to several gun positions.
These phones were powered by six pattern 1453 cells in a pattern 1704 battery box[2] This box was separate and probably situated near one of the two phones.[Inference]
2108A and 2109A
As shown in the Torpedo Drill Book, 1914.
These were employed just as the earlier models, but now were suitable for use with a motor generator.[3] The 2108A's call-up button had been modified to be a two-way switch like a Morse key, allowing it to always call the gun position unless the 2109A's talk button was depressed. The 2109A's receiver was always online, and the 2108A's was online except when the bell push was depressed.
Judging from the images in the 1914 Torpedo Drill Book, these phones differed from patterns 2108 and 2109 by having their receiver horns projecting diagonally downward when they were mounted (down and left for the 2108A and down and right for the 2109A). The position of the push-to-talk levers suggests this may not reflect a difference in design between the 2108A and 2109A, but may instead mean that the 2109A was twisted 90 degrees counter-clockwise before being mounted. The drawings, sparse in detail as they are, also suggests that the A models also had the type of transmitter that was automatically rotated to shake up the carbon granules within as the lever was pressed.
The 2108A was also used, in modified form in some cabins in Dreadnought and later ships. In this application, it had a wall fitting and a table fitting. The wall fitting received the 4 wires from the remote station and contained a call-up bell, and sent a 6 wire cable to the desk fitting containing the receiver and call-up and push-to-talk buttons.
The transmitter was connected by a twin-core wire for a small degree of flexibility in use, and could be hung up by placing it face-down on a rest to disable the transmitter circuit and enable the local bell. The short trumpet projecting upward from the receiver could rotate in yaw.
This awkward arrangement was supplanted by the Pattern 541 Navyphone which much more closely resembled a modern wall phone.[4]
Service Life
These phones were almost certainly obsolete by 1924, by which time only phones in the [[Pattern 246X Navyphones]|2460]] and [[Pattern 333X Navyphones]|3330]] series were in general use.[5]
See Also
Footnotes
Bibliography
