This design, must realize a priority hospital bed ringing system. Simulates the hospital ward number code through the first encoder 74148 pairs, again carries on the code and the decoding through launcher VD5026 and receiver VD5026, hospital bed call information transmission to doctor duty officers observation room. When has the hospital ward calls the signal through logical gate low level triggering by 555 constitution monostable triggers, thus exudes 5 seconds cries, simultaneously demonstrates the hospital ward number through the nixietube monitor, by calling signal control thyristor, thus controls Guan Liang who corresponds the hospital ward warning light. The above presses replacement key R to be possible to reposition. This system has the perform reliably, the principle simple merit.
key word: Hospital bed callmaker; 74148; Launcher; Receiver; 555 timers
