Automatic remote reading system for electricity meters - uses microprocessor connected to supply company via public telephone network

摘要

The telemetry unit (1) is connected between a telephone subscribers appts. (2) and the line (L) to the public telephone exchange network. It is also connected to a number of electricity consumption meters (M1 to M4), via one or more 20 mA control loops. The control loop is connected to the unit microprocessor (3) via an input port interface (5). The microprocessor stores data in an EEPROM. When a reading is to be sent to the supply company, the processor switches (9) the line interface (8) to the output of a modem (4, 6) system which converts the data from the processor to audio frequency FSK signals. The processor also has service (7) and auxiliary (11) ports.