PURPOSE: To attain the installation of the data communication equipment to an optional location within a distance limited due to a line loss independently of distinguishment of wire configuration when a network terminator and a 1st terminal equipment are provided and a 2nd terminal equipment is installed with respect to the data communication equipment provided with an I interface of an ISDN.

CONSTITUTION: The communication equipment is provided with a network termination section 9 inter-converting a subscriber line data and the data of an I interface, and the network termination section 9 and a 1st terminal equipment 4 are interconnected via a coupling section 3 including a variable delay circuit depending on a logic level and connected to a bus 7 via transmission reception sections 5, 6, and a delay of the variable delay circuit is controlled in response to the wiring configuration of the 2nd terminal equipment 8 connected to the bus 7 to synchronize the transmission signals of both terminal equipments 4, 8.