| 摘要 |
PURPOSE:To connect a packet switching board while using a standard interface by adding an interface device to a line switching board having an ISDN interface. CONSTITUTION:The interface device consists of an equipment 3a interposed between an ISDN terminal and a line switching board 1a and a device 3b interposed between the board 1a and a packet switching board 2. The interface device 3a is a network termination of an ISDN interface layer 2 to demultiplex B and D channels, demultiplexes a signal of the D channel into a control signal and a D channel packet and converts a protocol of a layer 2 in the case of a D channel packet. Moreover, the interface device 3b has a function DCE as to an ISDN terminal 4 connecting to the line switching board 1 and a function as a DTE to the board 2 and a public ISDN network 15.
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