Navigation device S-Phone type 13/MKIV 1943

The device is held above the belt by two buckled straps. When unfolded, the antenna plugs into its connection point. The operator can adjust the frequency in order to obtain optimal audio quality. The straps are attached to a belt with seven mesh pouches: five of them contain 10 miniature nickel-cadmium accumulators; the other two pouches house the vibrator (an electromechanical device that converts a DC electrical supply into pulses that can be fed into a transformer) power supply, the headset, and folded antenna. When the device is not operating, the S Phone functions in duplex mode, which means the user does not need to do anything to switch from emission to reception, its bilateral communication working in the same way as with a normal phone.