| 摘要 |
PURPOSE:To reduce the effect of the space of installation, the external noise, etc. for a branching device that connects plural terminal devices to a center via a communication circuit, by installing a modulating/demodulating circuit which is used for an interface to the communication circuit at the center side within a branching device. CONSTITUTION:A branching device consists of a main control circuit 7, a channel control circuit 8 and a modulating/demodulating circuit 10. The circuit 7 transmits the transmission request signal to the circuit 10. When the transmission permitting signal is sent back to the circuit 7 from the circuit 10, the circuit 7 selects either one channel based on the prescribed priority and transmits a transmission indicating signal to the circuit 8. The circuit 8 transmits the transmission permitting signal to the channel selected based on the transmission indicating signal to connect the transmitting data circuit of the corresponding channel. The circuit 10 converts the transmitting data into the AC signal to transmit it to a communication circuit 3. The AC signal of the circuit 3 is converted into the DC signal by a modulating/demodulating device 2 of the center side and transmitted to a center 1. |
