PURPOSE: To easily set a call by giving an extension number to combination of information elements required for call setting to an ISDN terminal connected to a private branch exchange or the like.

CONSTITUTION: In an extension number table, an extension number 300 is set to the combination of information element 'speech' of the transmission capability, information element 'voice' of the lower-order layer matching, and information element 'telephone' of the higher-order layer matching. In the same manner, an extension number 301 is set to the combination of information element '3.1kHz audio' of the transmission capability, information element '3.1kHz audio' of the lower-order layer matching, and information element 'G2/G3 facsimile' of the higher-order layer matching, and an extension number 302 is set to the combination of information element 'nonlimited digital' of the transmission capability, information element 'nonlimited digital' of the lower- order layer matching, and information element 'G4 facsimie' of the higher-order layer matching. In this case, the interface number in the extension number table indicates the number of an ISDN terminal interface.