The document deals with customer premises cabling for the connection of primary access ISDN equipment. It specifies: design requirements for cabling in the point-to-point-configuration and the installation of new cabling, criteria for the use of existing cabling and the implementation of ISDN primary access on structured cabling systems. These requirements also apply to wiring between ONP 2048 kbit/s network interfaces and terminal equipment conforming to DIN ETS 300248.#,,#