Transmission and Multiplexing (TM); Physical and electrical characteristics of hierarchical digital interfaces for equipment using the 2 048 kbit/s - based plesiochronous or synchronous digital hierarchies
传输和多路复用(TM);使用基于2 048 kbit/s的准同步或同步数字层次结构的设备的分层数字接口的物理和电气特性