System capacity: 100 households Visitors identified function. Non-visual extension is not compatible. Visual extensions are endued function of voluntary monitoring. Conversation up to 120 seconds.
Noctilucent keyboard High-performance CCD camera, with infrared illumination, you can easily identify visitor even in backlighting or the luminance is as low as 0.1 Lux Confidential conversation
and wire design is six-bus + one video wire.