The communication mode can be switched between encrypted and non-encrypted via one of the programmable push buttons at the radio.

The encryption is implemented using the voice inversion technique. The inversion frequency is factory pre-set, but can be changed to customer specifications.

The VIM module is inserted in the audio transmit path before the pre-emphasis and in the receive path after the de-emphasis. Degradation of the audio quality in encrypted and non-encrypted mode is subjectively not noticeable.

The module is for installation inside the radio next to the speaker. It is interconnected with the radio control board via colour coded wires.

The dimensions are 4/6 x 29 x 16/19  mm.