• Perfect Electronics

Cordless intercom, mains operated

Satara-based Perfect Electronics has recently introduced an educational kit, a cordless intercom. one set of intercom consists two units. Each unit operates on AC 230 mains. When the slide switch is taken at the On mode of first unit, and if the push switch is pressed, then audio tone is produced from the second unit; and if the slide switch is taken at On mode of the second unit then the audio tone (ring) stops. Now if voice is produced in front of the microphone by pressing the push switch for first unit, voice is produced from the second unit and if sound is produced in front of microphone in second unit by pressing the push switch, the voice is produced from the first unit. Phase Lock Loop (PLL) technique is used in this intercom. Carrier frequency used is 140 kHZ and audio signal is FM modulated so sound quality is good. There is no static noise in the receiver when there is no signal. The range is 300-500 metres along the main line. It requires the same mains phase line, but if the main transformer of electricity board is in between the two units and within specified range, then it is not necessary to have the same phase line. It can be used in offices, or in the same campus for the speech communication. The company offers technology transfer at attractive rate, which includes circuit diagram, details of PCB and films of PCB.