Hello, everyone!
I'd like to share with you a case when the alarm indicator is off because the alarm cable is not connected.
Diagnostic
During a new project, an NE (OSN 8800) is configured with one master subrack and three slave subracks in two cabinets. Slave subtract 1 and the master subrack share one cabinet, while slave subracks 2 and 3 share the other cabinet.
During commissioning, the alarm indicators at the top of the cabinet in which subracks 2 and 3 reside and the alarm indicators on the FAN in subracks 2 and 3 are off when the boards in subracks 2 and 3 report a large number of alarms.
The alarm indicators at the top of the cabinet in which the master subrack resides and the alarm indicator on the FAN in the master subrack are on when the boards in the master subrack report alarms.
Cause analysis
The alarm drive signal output through the LAMP1 or LAMP2 port in the subrack port area drives the four alarm indicators at the top of each cabinet. Therefore, the cause of the problem that the alarm indicators on the FAN in certain subracks are off should be found out first.
The master subrack drives the alarm indicator on the FAN in each slave subrack. Therefore, if the connection of the indicator/alarm concatenation cable between the master subrack and a slave subrack is incorrect or absent, the preceding problem will occur. Subracks 2 and 3 where the problem occurs, however, are in the same cabinet. It indicates that an inter-subrack indicator/alarm concatenation cable between the two cabinets is probably not installed during the hardware installation.
Procedure
Check the alarm cables for the alarm indicators at the top of the cabinet where the master subrack resides and the indicator/alarm concatenation cable between the master subrack and slave subrack 1. The check result shows that the LAMP2 port on the master subrack is connected to the drive port for the alarm indicator at the top of the cabinet, while the LAMP1 port on the master subrack is connected to the LAMP2 port on slave subrack 1.
Check the alarm cables for the alarm indicators at the top of the cabinet where subracks 2 and 3 reside and the indicator/alarm concatenation cable between subracks 2 and 3. The check result shows that the LAMP1 port on subrack 2 is connected to the LAMP2 port on the slave subrack 3.
The cause of the problem is that the indicator/alarm concatenation cable between the LAMP1 port on subrack 1 and the LAMP2 port on slave subrack 2 is absent. Use a straight-through network cable to interconnect these two ports. Then, the alarm indicators on the FAN in subracks 2 and 3 will be on in case of alarms. In this manner, the problem is solved.
Reference information
The master subrack drives the alarm indicator on the FAN in each slave subrack. Therefore, the alarm indicator on the FAN in each slave subrack functions normally only under the condition that the indicator/alarm concatenation cable between the master subrack and each slave subrack is correctly connected.
The alarm cables for the alarm indicators at the top of a cabinet and the inter-subrack indicator/alarm concatenation cables in this cabinet are connected before delivery. The inter-subrack indicator/alarm concatenation cables between cabinets, however, need to be routed and installed during hardware installation on site.
The ALMO1 and ALMO2 ports are two alarm output concatenation ports. Generally, the alarms of an NE are used only after they have been sent to a monitoring device (such as a centralized alarm distribution cabinet). The LAMP1 and LAMP2 ports on a subrack are used to drive the running indicator and alarm indicators at the top of the cabinet in which this subrack resides. The 'alarm indicator' refers to the alarm indicator on the FAN in this subrack. Therefore, the LAMP1 and LAMP2 ports can be regarded as indicator concatenation ports.
That's all, I welcome everyone to leave a message and exchange in the comment area!
Thank you！
