1. Field of the Invention
The invention disclosed here relates generally to remote control of computerized equipment and more specifically to remote control of the power supply of a computer system and/or other electrical devices.
2. DESCRIPTION OF THE RELEVANT ART
The advantages of being able to turn on and off the power supply of a computer system located at a remote site are well known. U.S. Pat. No. 4,206,444 "Remote Power Controller Utilizing Communication Lines" issued June 3, 1980 to Ferlan, for example, discusses the advantages of reducing power consumption and the danger of unintended turn-on. The Ferlan disclosure is incorporated herein by reference. According to the Ferlan patent, a comparator is interposed at the remote site between a modem and a gate activated power relay. The comparator scans through incoming serial signals from the modem searching for a predetermined sequence, and when this sequence is detected, the gate controlled relay is turned either on or off to thereby supply electrical power to a computer power unit.
A disadvantageous aspect of the Ferlan design is that incoming messages to the modem must be restricted so that the predetermined power turn-on or turn-off sequence is not included when such turn-on or turn-off is not desired. It is possible for binary bit stream to randomly include this sequence, and if such a sequence is randomly generated, an undesirable activation of the power controlling relay may take place.
Another disadvantage of the Ferlan design is that the receiving modem at the remote site needs to be closely placed to the power control unit and to the computer which is to be turned on or off. This limits the flexibility of users in being able to move their computer equipment from one location to another within the remote site without having to also move the receiving modem and its adjunctive telephone wires.
Other works in the field of remote control which Applicant is aware of include U.S. Pat. No. 4,701,946 "Device for Controlling the Application of Power to a Computer" issued Oct. 20, 1987 to Oliva, et al.; U.S. Pat. No. 4,723,269 "Method and Apparatus for Power-Up of Unattended Computer" issued Feb. 2, 1988 to Summerlin; U.S. Pat. No. 4,647,721 "Telephone Activated Power Controller" issued Mar. 3, 1987 to Busam, et al.; U.S. Pat. No. 4,809,163 "Computer System with Power Control Based on the Operational Status of Terminals" issued Feb. 28, 1989 to Hirosawa, et al.; and U.S. Pat. No. 4,812,963 "Plural Cooking Computer Communication System" issued Mar. 14, 1989 to Albrecht, et al.