Loudspeaker Mystery

[David Dunlop]

A few decades ago, one could trip over these things in virtually any surplus store in Manitoba for about $5.00 each and I picked up two sets. Not that I knew anything about them. It was just because they had “NO. 19 SET” stenciled on them, and I was on the hunt for anything related to that particular wireless set.

Still have them today and decided it was about time I figured out what they are all about. I have never seen one in original World War Two configuration. All the ones I have come across are like the one shown below, painted over with 1950’s gloss OD. I chose this one for photos because some original colour and markings are still visible, either on the surface, or under the 1950’s repaint. If anyone has an original they can post detailed pictures of, it would be most helpful.

What I do know about them is they were clearly designed for outdoor use. The speaker is weatherproof in design and there is a large black rubber weatherproof pushbutton on the top of it. To me, that rules it out as being intended for any sort of PA System. Speakers would only be useful if you are either dealing with communication to a number of people in a large space, or a small number of people in a very noisy space.

The pushbutton on the top has the stencil “PUSH TO SIGNAL” in front of it. And the two upper terminals have “LINE” stenciled between them. Crowds listening to a PA System, typically do not need to signal anyone, so to me, the use of these loudspeakers as part of a PA System seems very unlikely. The two terminals at the bottom of the unit have “NO. 19 SET” stenciled between them. That is what caught my attention in the first place, but it is also the prime piece of the mystery. To the best of my knowledge of the 19-Set, there is no way for a direct connection to be made from this loudspeaker to the 19-Set. There must be an intermediary piece of equipment, between the 19-Set and the loudspeaker which will allow the three pieces to interact with one another correctly.

So I am now thinking, these loudspeakers are probably part of a ‘kit’. The kit probably consisted of one or more pairs of these loudspeakers, one or more reels of a four conductor land line, some sort of control/switchboard interconnection unit and some set of adapter cables to patch the 19-Set into the interconnection unit. Would this mean this equipment was intended to be used as part of a communications system for an artillery or mortar battery, with its related command or fire control center?

I seem to recall there is either a CMP truck, lorry or trailer intended as a fire control center. Would it have held a 19-Set and the intermediary equipment and have had land lines feeding out to the gun or mortar crews to provide instructions? If so, the instructions seem to be a form of one way communication. How would the crews have communicated back to the wireless operators, beyond pushing a signal button?

If anyone can enlighten me, I would be greatly appreciated and if there is a Canadian Army publication in existence detailing this equipment and its usage, I would love to find a copy.

Best regards.
David