The present document specifies the physical and electrical characteristics (except safety, over voltage and EMC aspects), the necessary functional characteristics and the corresponding test principles for a terminal equipment interface for connection to the Network Termination Points (NTPs) of Open Network Provision (ONP) 2 048 kbit/s digital structured leased lines using 120 §Ùinterfaces with an information transfer rate of 1 984 kbit/s without restriction on binary content.