The history of interphone

The technology of interphone was first born in 20s, and was born in the laboratory of Westinghouse. A curious inventor named John Kermode, who wants to automatically divide the postal documents, is curious about every idea of the application of electronic technology. His idea is to make a walkie talkie mark on the envelope. The information in the intercom is the addressee's address, just like today's zip code. To this end, Kermode invented the earliest interphone logo, the design is very simple, that is, a "bar" to represent the number "1", the two "bar" to represent the number "2", and so on. Then he invented the interphone literacy equipment composed of basic components: a method of measuring the reflected signal strip and air, that is, the edge positioning coil, and the method of using the result of the measurement, that is, the decoder.