Loudspeaker Mystery

[Johnny Canuck]

Hello David
Telephone Loudspeaker was used to control a battery of 25 pdr's or 4.2" mortars.
The L.S. No.2 Canadian Control Unit was located at the CP and connected to the Loudspeakers by 2 wire cable. The CP could send instructions to the guns and the guns could reply by pressing the Push button and then yelling into to speaker to send a reply.

Some scans from a 1943 British 4.2" Mortar Manual.

Geoff

[David Dunlop]

Geoff:

Thanks for the additional information. Every little bit helps in better understanding this equipment.

I had considered the speaker being used to 'mic' back information, as electronically there is little difference between mic and headphone element design/function, but the rather robust look of these speakers made me hesitate about that possibility.

I dug up a second speaker and it has been repainted so much all traces of original stencils are long gone and just the 'PRESS TO SIGNAL" new printing is visible. I have a second pair tucked away somewhere and must track them down to see what they can tell me.

Is the Control Unit a rare bird? With the large numbers of speakers that used to be lying about in these parts, I am puzzled I have never spotted the Control Units or manuals.

David