British AFV Intercom


This article was kindly supplied by Derek Gardner, England .

One of the priorities within a restored armoured vehicle for driving on the road has got to be the intercom. Most Radio sets have a built in IC function but this means a drain on battery power and also the purchase of a very expensive Radio set.
With the IB3 and the later clansman replacement you have an excellent unit that can be fitted into a vehicle, or made as a temporary plug in unit, as some owners of more than one vehicle do. The whole set can be bought for between 80-100, and is a very economic way of providing intercom.

The heart of the unit is the IB3 or later Interconnecting box - 2 Radio (Nato stock No 5820-99-117-6250). This is basically a junction box for connecting the radios within the vehicle to the harness that runs around to all crew stations. The older IB3 is a smaller unit, of square design whereas the later unit is larger and has a more rounded appearance. The functions are basically the same with a built in amplifier to provide intercom independently of the radios as well as controls for switching and mixing between two radio sets A and B and intercom, allowing you to have any combination of intercom in one ear and A or B set in the other. The unit functions on a 24volt supply and is connected into the harness that runs around the vehicle. You also have the facility for connecting a telephone hand set for remote use using twin cable.

Pictured below is the Intercom itself.

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The harness can be customised to cater for all types of vehicle with different combinations of crew boxes. Each crew box allows for the connection of two head sets, as well as the facility to switch and mix A and B sets and intercom, with individual volume controls.

A crew box .
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The layout in my Ferret is the later unit fitted with two crew boxes allowing for up to 4 headsets. The head sets that can be used are either crew helmet type or later crew head sets which incorporated an ear defender facility to cut out the background noise. The head sets are fitted with crew extension leads that incorporate pressel switches to cut the microphones when not in use, this stops a lot of the background noise. The crew leads can also be set with the pressel open for the driver allowing hands free control. Another useful addition is a 30ft extension lead that can be run out from the vehicle allowing the commander to get out of the vehicle and still have contact. Within my set up I have included a Interconnecting Box - Drivers Box Selector (Nato stock No 5820-99-117-5041) you have not got the facility of connecting headsets to this unit but it has a very useful warning light that shows when the unit is switched on.

The driver's box .
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Well I hope that this will give some guidance on what equipment is required to provide an authentic intercom unit within a post war British vehicle. I am not an expert on army radio equipment so I am happy to stand corrected, but I have a good functional intercom within my ferret an this was achieved at a reasonable cost.

Derek Gardner

My thanks to Derek for the article and photos.

Click here for British Intercoms part 2.


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