The rainbow cabinet and chassis also had non-radio uses. Northern Electric manufactured a office intercom system that used both. This is the non-powered unit that Northern Electric called the "Magnaphone Junior Substation". Basically the chasis contained a speaker and a flip-switch to microphone function and nothing else.

Tube Complement:

None

1. The typical plastic dial lens cover is painted black from the inside. The outside of the dial cover is painted with gold lettering.

2. The same two-hole rainbow cabinet used in the Model 5000 is used in the Model R4B.

3. The right hole accommodates a painted metal plug

4. The left hole accommodates a flip switch which allows the speaker to function as a microphone.

6. The back one five row of terminal screws labeled "A", "B", and "C" which allows it to be connected to a powered R6A station.

7. A bakelite back cover is used to conceal the back wiring connections allowing placement on an office desk.