The optical module is faulty or not securely installed. If the transmit optical power is abnormal, replace the optical. Most genuine Cisco and high-quality third-party compatible modules support this. Use the following command in the CLI: Or, to check a specific interface: Here is a typical output from a healthy connection. Transmit Alarm Alarm Warn Warn (C) (Volts) (mA) (dBm) (dBm). Customers in the use of optical modules will more or less encounter a variety of failure problems, such as optical module model selection is correct, the use of jumper is correct and some common problems, customers have the ability to judge and have a clear solution, but for some of the use of. Digital Diagnostic Monitoring (DDM), also called Digital Optical Monitoring (DOM), is one of those small features that saves hours in the field. Built into modern SFP/SFP+/ SFP28 /QSFP family modules and standardized by SFF-8472, DDM/DOM exposes real-time values for the module's temperature, supply. SFP or SFP+ optical transceiver failure can happen in multiple recognizable ways. The most notable fault is the “module not detected” error, which describes a situation in which a switch cannot detect the transceiver. This is a result of hardware failure, poor connections, or firmware errors, and. This command is powerful, directly show you the optical module send ( TX ) and receive ( RX ) optical power value, also with a health range ( high / low threshold ). That's the core of diagnosis 1.