| 摘要 |
The apparatus uses electric power lines to send and receive command, control, and data signal structures. Message signals are superimposed upon the AC power signals present on existing power lines. Transmit and receive sets are equipped with a unique individual coding (for identification and security) to complete the communication links. When a message signal is sent onto the line the unique code of the sending unit is placed at a predetermined position in the transmitted signal, such as in the header. Also the intended receiving unit code is placed in the message signal. In this manner, an individual receiving network at a given location will be activated only when its unique code has been placed into a message on the line sent by another unit. This coding ensures that only the intended location receiver will be able to "trap" the signal. The signals sent will be mid to high frequency and will be composed of low level logic/digital bits.
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