Data collection, storage and transmission system - uses multiplexer to allow transmission via telephone line to central processor through MODEM and interface

摘要

The device is connected to the processor by a telephone line. A telephone network connection circuit is linked to a processing unit which is also connected to the data providing devices. The network connection circuit includes a call detector and a call circuit connected to a network line, this line adjoining a network junction which is connected to a 2 wire/4 hybrid circuit. The reception output of this circuit is connected to a reception filter. The transmission input is connected both to a data transmission filter and to a tone transmission filter. The processing unit comprises a microprocessor connected by a bus to program memories and data memories, a multiplexer and a time reference circuit. The system may be used for transmission of data relating to temp., presence etc.