| 摘要 |
PURPOSE:To prevent degradation of the transmission quality, by setting plural busses between outgoing and incoming exchanges through a repeating exchange to transmit call signals of telephone lines, whose number is larger than the number of busses, by multiple band compression devices at both ends of busses. CONSTITUTION:When the telephone line outwent from exchange 7 and terminated by exchange 8 is set, the call request signal is transmitted from exchange 7 to exchange 8, and it is scanned by monitor parts of exchanges 7 and 8 whether an idle channel exist on transmission lines 1 and 2 between exchange 7 and repeating exchange 10 and between exchanges 10 and 8 or not. If the idle channel exist, the connection request is transmitted to exchange 10 to connect respective idle chanels of transmission lines 1 and 2 by exchange 10. Thus, the telephone line is set between exchanges 7 and 8 through repeating terminal 11 of exchange 7, repeating terminal 12 of exchange 8 corresponding to this terminal, and multiple compressing devices 4 and 5. As a result, even if multiple compression is performed through the repeating exchange, the degradation of transmission quality is prevented. |
