| 摘要 |
<p>In a private branch exchange connected to an Integrated Services Digital Network, an ISDN user interface unit separates a signal from each user terminal into a B-channel packet and a D-channel packet and further separates the latter into a signaling message and a D-channel packet mode signal. The separated D-channel packet mode signal is multiplexed with D-channel packet mode signals from other user terminals into a D-channel packet mode multiplex signal and applied through a channel to an ISDN network interface unit, while the signaling message is applied to a controller for processing. In the ISDN network interface unit, the D-channel packet mode multiplex signal is multiplexed with the signaling message processed by the controller into an outgoing D-channel signal and transmitted with the B-channel packet to the ISDN.</p> |
