This ETS specifies the full physical and electrical characteristics@ 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 kibt/s digital structured leased lines using 120 ?C interfaces with an information transfer rate of 1984 kbit/s without restriction on binary content. This ETS is not intended for regulatory purpose. A separate TBR (prTBR 13) covers the essential requirements for attachment under the Second Phase Directive (91/263/EEC). The ETS is to ensure that the interface of the terminal equipment is compatible with the ONP 2 048 kbit/s digital structured leased line. A terminal equipment interface that conforms to this ETS will also be compatible with an ONP 2 048 kbit/s unstructured leased line. This ETS is applicable to all interfaces designed for connection to the leased line@ However in the cases of apparatus that carries a particular service@ of complex apparatus and of apparatus in private networks@ other ETSs may apply in addition to this ETS.