Simplebus system audio-video unit with terminal board complete with camera pin-hole CCD 1/4' black and white adjustable from the front, and LED camera illumination. Complete with audio speaker unit with double amplifier, watertight loudspeaker and electret microphone. Both, microphone and loudspeaker volumes, can be adjusted from the front. To be inserted in modules arts. 3321/0, 3321/1 and 3321/2. Dimensions: 102x55x35 mm