ETSI PRETS 300 166-1993 传输和复用(TM).基于准同步或同步数字系列的2,048 Kbit/s设备的系列数字接口的物理和电气特性
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