PURPOSE: To perform a quick maintenance service by collecting communication record or protocol trace related to G4 facsimile equipment connected to the Integrated Services Digital Network(ISDN) from a remote place and also, by using G3 facsimile equipment appropriately.

CONSTITUTION: A specific password is set after inter-network connection is performed between the ISDN 100 and a telephone network 200, and the remote reception of the communication record or the protocol trace stored in the filing part of the G4 facsimile equipment 100A in the ISDN 100 that is the object of maintenance can be performed by using the procedure of the G3 facsimile equipment or that of the G4 facsimile equipment. Therefore, the polling of communication managing information can be performed by an inter-working function between the ISDN 100 and the telephone network 200 not only from the G4 facsimile equipment 100A but from the G3 facsimile equipment 200A in a public telephone network. In such a way, the maintenance service can be performed efficiently from all places by utilizing characteristic in the constitution of the network of the G3 facsimile equipment 200A.