19 Control Unit No.2 MkII
on RHS of the tank. Top switch has two positions, N for Normal
operation and R.
normal mode the lower switch selects between the A set, B set
R has two uses:- "through calls" and Re-braodcast.
calls enable a distant station on the A net to communicate directly
with a distant station on the B net, the control unit acting as
a 'telephone exchange'. can be made from stations on the A set
to stations on the B set., although the operator must move the
selector switch each time the direction of message changes.
is the permanent or temporary relaying of all transmissions on
the A net of one vehicle to the B sets of all other vehicles.
black object to upper right is in fact a 'red' bulb which lights
was a warning when the A set is left unattended.