This paper presents the design, construction and testing of a simple multi-station, intercom system for use by a master and remote stations. All the electronic circuitries are contained in the master station while a remote station contains only a loudspeaker, a push – button switch and a capacitor. A call facility was incorporated in the system which allows the master station user to call a remote station and vice – versa. A display unit, made up of LEDs is provided on the master station console, which indicates to the master station user, a particular calling remote station. The display unit and the call facility are connected in such a way that the use of one push button switch provided at the remote station activates them simultaneously. The constructed unit has one master station and two remote stations with provisions to increase the number of substations. The system is built around some popular and cheap ICs so as to provide cheaper alternative to the imported types.
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