可信时间戳机构    trusted time stmping authority

隧道标识    Tunnel Identifier TID

电路复原信号（    TUP） Circuit Reset Signal RSC

双绞线    Twisted Pair FTP

双纤双向线性倒换环    two-fiber bidirectional linear switched ring

双纤单向通道保护环    Two-fiber unidirectional path protection ring

双向中继    Two-way trunk, bidirectional trunk

BNC    T型接头 BNC T Connector