Remote control of electrical equipment e.g. computer

摘要

A computer (1) is connected to a modem (2) and converter (3), which converts RS232 signals into TTL logic. A micro-controller (4) monitors the RS232 connection for Data Set Ready (DSR), Data Terminal Ready (DTR) and Data Carrier Detect (DCD) signals. It also controls the computer ON/OFF switch (5). The use telephones in via the modem, which activates the microcontroller. DTR and DSR signals establish whether the computer is already switched on under logic control. The computer allows the user to assume remote control. Breaking the telephone connection initiates a controlled shut-down sequence.