| 摘要 |
PROBLEM TO BE SOLVED: To attain miniaturization and simplification of a system by making it possible to directly connect a subscriber line interface circuit or the like which constitutes an analog port without using a logic circuit external to an interface circuit for the analog port of an ISDN terminal adapter. SOLUTION: An interface circuit A1F for an analog port control composed of a microprocessor central processing unit(CPU) for connecting to an ISDN circuit network, a control register(CR) controlled by this microprocessor CPU and a control logic(CL) in which an operation is controlled by the CR is prepared on a chip of an integrated circuit(IC). The analog port is made to be able to be directly connected to a semiconductor integrated circuit for an ISDN terminal adapter.
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