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 kbit/s digital structured leased lines which support an unstructured 1 984 kbit/s information transfer rate using 120 ?? interfaces. This ETS is not intended for regulatory purposes. A separate TBR (TBR 13) covers the essential requirements for attachment under the Second Phase Directive (91/263/EEC). This 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. Customer premises wiring and installation between the terminal equipment and the NTP are outside the scope of this ETS.