protection span

A section of a carrier transmission system, including repeated line and in some cases terminal equipment, within which a broadband protection channel can be substituted for a working broadband channel in the event of equipment or line failure in the working channel.; 載波傳輸系統的一區段,包括重復的線路,有時還包括終端設備。在工作信道中的設備或 線路出現故障的時候,一個寬帶保護信道可以替代正在工作的寬帶信道。