This TBR specifies the attachment requirements and corresponding test principles for a terminal equipment interface for connection to the Network Termination Points (NTPs) of ONP 2048 kbit/s digital structured leased lines (D2048S) using 120 õ interfaces with an information rate of 1984 kbit/s without restriction on binary content. A terminal equipment interface that conforms to this TBR will also conform with TBR 012 for connection to an ONP 2048 kbit/s unstructured leased line.