A vedio-talkback and information publishing
system for the building is composed of several sets of indoor machines, several decoders, outer gate machines, supervisors and central computer, in which includes the talkback
audio frequency circuit, vedio frequency circuit,
crystal lattice display circuit, alarm circuit, monitoring circuit and entrance guard
system, all the abovesaid equipment being connected in the net by the communicating of 485 data
bus mode, Each equipment will be connected to the data
bus by their own data receiving-transmitting circuit to realize the mutual speaking with each other between the supervisor, indoor and outer gate
machine, to realize the detection and control by
control circuit as well as to realize decoding by decoder. The central processor of each equipment applies 51 series
single chip computer and the circuit applies the modularization design to form a integration
system for vedio shooting, talkback, alarm, leaving
massage and information publishing of the building and various kinds of residential quarters.