How To: New Wire-5 project (Bergeron)

[Robert Bergeron]

This telephone switchboard is going in the box with the corresponding 6 field phones . Can someone tell me the voltage of the battery needed to operate the switchboard please ?

[Chris Suslowicz]

Without looking it up, 4.5 volts. Originally there was an open-topped aluminium box that held 3 'X' or 'S' cells and slid into the brackets o the floor of the case, but I suspect they started using 126 or similar batteries at some point.

I have the manual and will look it up in a moment.

There should be slip-on weights with built-in pulleys for each of the connecting cords, and you alternate red and black cords to reduce confusion.

Chris.

[Chris Suslowicz]

(One practical demonstration of Boob's Law[1] later...)

Switchboard UC 6 line with battery and Box, Accessory, Switchboard UC 6-line containing 7 pulley weights and cords; operator's Telephone, Hand, No.2; Night Bell and connector. Weight 35 lb. 6 oz.

The current for the switchboard is provided by a battery of three cells (Cells, Dry, X, Mk.II; or Cells, Dry, Inert S, Mk.I) contained in a removable box behind the line units in the back of the case, connections being made to the battery box by means of plugs and cords. Terminals are provided on the line terminal panel at the back of the switchboard for the connection of an external battery if desired.

(Pulley weights are apparently optional for the 6-line version.)

The battery box has sockets on the end to take the two plugs from the switchboard.

Best regards,
Chris.

[1] You always find something the last place you look - I think I found manuals for everything between the pre-WW2 "Mark 236" and the postwar 40/160 Line Exchange before the Switchboards UC 10-line and 6-line pamphlet turned up!

[Robert Bergeron]

Thank you very much Chris ! 4.5 Volts then . The field phones run on the same voltage i assume ? Boob’s law ?

[Chris Suslowicz]

Hi Robert,

Boob's Law - see footnote [1] on my previous post.

Field Telephones for WW2 Commonwealth forces would be the D Mk.V for front line forces, Telephone Set 'L' for Linemen, and Telephone Set 'F' for higher formations (basically an office telephone for people with desks). All of those ran on 3 volts from a pair of 'X' or 'S' cells. Switchboards for higher formations would be the Switchboard F&F (Field & Fixed)which could support 20 to 60 lines and could operate with three switchboards in parallel as a combined unit.

Switchboard UC "Universal Call" supported buzzer and magneto signalling.
Switchboard F&F is magneto only.

Telephone set D Mk.V was buzzer call but buzzer or magneto ring
Telephone set 'F' was originally buzzer and magneto signalling but the buzzer was replaced by an induction coil (microphone transformer) later on (for better audio quality) and became magneto only.
Telephone set L was magneto signalling (only).
(There may have been some earlier (Post Office 110) telephones still used by linemen, but the 'L' was rather better.)

(Plus the various Remote Control Units (Canadian) and the British 'E' could connect to switchboards as magneto telephones, of course.)

All the manuals are available from the WS19 website - I think I scanned most of them.

Best regards,
Chris.

[Robert Bergeron]

Thank you for your detailed answer Chris - Wanted : Look at pictures . I want to set up an artillery comm truck so i need these to complete the CES. Photo credit : Bruce Parker .

[Robert Bergeron]

Built a homemade Tannoy speaker today to listen to the WS No 19 set . Still looking for an amplifier to connect to one of the drop plugs but the search is narrowing .