| 摘要 |
PURPOSE:To prevent contention and to attain ease of multiple address communication by providing a signal channel through which a control signal is transmitted from one station to all other stations when each branch point of a multi- drop private line system comprising N-set branches is equal. CONSTITUTION:The multi-drop private line consists of M-set of lines and N-set (N=4 in Fig.) of branch points are constituted. Multi-drop terminals MD11- MD1M...MD41-MD4M are provided accordingly and exchanges EX1-EX4 are placed to each branch point. Each exchange is provided with signal transceivers SR1-SR4, which are connected by 4 signal channels. Each channel is used for the transmission S and the other are used for the reception R. Any station is used as the master station and the master station selects and assigns the M-set of private lines. Each station transmits a request of private line selection to the master via the signal channel, and the master responds to it via the signal channel. Thus, the contention of each station is prevented and the multiple address communication is conducted easily. |
