单项选择题
A. DS-1; E1 B. DS-1; STM-1 C. OC-3; STM-1 D. STS-1; STM-1 E. OC-192; STM-192
SONET Path Terminating Equipment (PTE) requires which t...
多项选择题SONET Path Terminating Equipment (PTE) requires which three line codes to be supported for DS1 and DS3 circuits?（） (Choose three.)
A.AMI B.ESF C.DUS D.SSM E.B3ZS F.B8ZS
Which timing mode is appropriate for a SONET NE that is...
单项选择题Which timing mode is appropriate for a SONET NE that is adjacent to a SONET NE using BITS-1 timing source?（）
A.DUS B.line timing C.loop timing D.internal timing E.through timing
If node 2 is accepting line timing from node 1, node 2 ...
单项选择题If node 2 is accepting line timing from node 1, node 2 will send （）to node 1 as its SSM message.
A. ESF B. PRS C. DUS D. SMC E. B8ZS
