Alarms of the same type with different names

In the E1 telecommunication signal interface board, its PDH interface external signal loss alarm is the T_ALOS alarm; in the E3 telecommunication signal interface board, the P_LOS alarm is used; in the E4 telecommunication signal interface board, the alarm is expressed by EXT_LOS.

In the E1 telecom interface board, a detected signal of all "1s" in the downstream signal flow will report DOWN_E1_AIS alarm, and a detected signal of all "1s" in the upstream signal flow will report UP_E1_AIS alarm; in the E3 telecom interface board, it will report P_AIS alarm. In the E3 telecommunication interface board, the P_AIS alarm is reported; in the E4 telecommunication interface board, C4_R_LAISD is used to indicate that the net load is detected as all "1s" in the downstream direction, and C4_T_LAISD is used to indicate that the net load is detected as all "1s" in the upstream direction.

Different channel overhead bytes used for alarms and performance event monitoring

The channel overhead bytes used in the E3 Telecom Interface Board and the E4 Telecom Interface Board are the B3, J1, C2 and G1 bytes. The B3 byte is used for error code monitoring, using even-checked BIP-8 code, and its role is the same as that of the V5 byte b1-b2. The J1 byte has the same role as that of the J2 byte, and the C2 byte is a signal marking byte with the same role as that of the V5 byte b5-b7. The G1 byte is used for generating the alarm backhaul, and its structure is shown in Fig. 1.

Figure 1 Structure of G1 byte

Among them, the b1-b4 encoding meanings of G1 byte are:

• 0000-1000 means that there are 0 to 8 error codes respectively.
• 1001-1111 indicates that there is no error code.