The circuit provides a simple illustration of a door phone intercom system having a two-way communication using the features of LM386 amplifier. Intercom – short for intercommunication, is an ...

If you were to ask people outside our industry what door and access security entails, chances are their answers would reflect their common encounters with locks, security guards, c... Enhancing ...

with (500D phone) CP109 surface panel, speech unit, controller. Larger systems available a ...