| 摘要 |
PURPOSE:To enable normal signal delivery, if emergency power supply is used for the master and slave units constituting alarm unit in case of power failure and disconnection, by supplying power from master to slave unit and enabling signal transmission between the master and slave unit. CONSTITUTION:Two lines are connected between the master 1 and slave unit 2 located at remote place. Power is delivered to the slave unit 2 with DC intermittent voltage intermitting DC voltage with a given period from the master unit 1, and the signal having the frequency in different period than the intermittent voltage of the DC intermitent voltage. In this case, the start signal So is superimposed on the DC intermittent voltage and the transmission of signal is identified through the reception of the slave unit 2. The DC intermittent voltage succeeding to this signal So is determined sequentially as the first... Nth channel and signal is transmitted by superimposing on each channel signals S1...SN. |
