| 摘要 |
PURPOSE:To attain the exchange of D channel packets without changing the function of a circuit exchange processor with use of an ISDN switchboard. CONSTITUTION:A D channel. signal separating/uniting circuit 17 separates the D channel control signal into a circuit exchange control signal (sapi=0) and a D channel packet exchange control signal (sapi=16) according to the contents of a service access point identifier (sapi). The D channel control signal is received from an LAPD 3a of a subscriber circuit 2a of an ISDN switchboard. Then a D channel packet device 15a received the separated D channel packet exchange control signal. A D channel packet layer 2 control circuit 16 applies the layer 2 processing to the signal outputted from the device 15a. Meanwhile the circuit 17 unites both signals outputted from a circuit exchange processor 9 and the device 15a and inputs these united signals to the LAPD 3a of the circuit 2a.
|
