Design and Implementation of Eight-Way Call System Based on Digital Integrated Circuits

Abstract

This paper introduces the construction of an eight-channel call system using medical callers. The circuit enables the call signal to be sent to the 74HC148 priority encoder for encoding if any of the channels make a call. The encoded signal is processed by the 74LS283 and then output from the 74LS373 latch to the 4511BD decoding and driving circuit. The output of the decoding and driving circuit is displayed on the display circuit, showing the number of the channel that made the call. Meanwhile, the control signal triggers a monostable oscillator circuit composed of a 555 timer, which generates a temporary stable output signal with a pulse width of about 2s. The pulse signal drives a multivibrator circuit composed of a 555 timer, which causes the LED to work and output an alarm signal. The alarm state can be eliminated manually by pressing a key.