A.Not above

B.E1 and E2

C.E1

D.E2

A.8

B.20

C.4

D.16

A.PCM30 frame format of E1 frame: except time slot 0 which is used as synchronization time slot and does not carry voice, time slot 16 also cannot carry voice because it is used to transmit random signaling.

B.SATop encapsulation type processes CES services by packaging the 32 time slots in the E1 frame as a whole and then transparently transmitting them to the other end.

C.PCM31 frame format of E1 frame: except for 16 time slots as synchronization time slots that do not carry voice, it can also carry 31 channels of voice.

D.The CESoPSN protocol can identify the structure of TDMN services. It does not need to transmit idle time slot channels. It only extracts useful time slots from the service flow and encapsulates them into PWE3 messages for transmission.

A.If a C2 byte mismatch is detected, an LP SLM alarm is reported in the corresponding VC-4 channel

B.C2=00H means VC-4 is not equipped

C.The C2 byte is used to indicate the multiplexing structure and payload attributes of the VO frame

D.The C2 byte to be sent must match the C2 byte to be received

A.True

B.Error