The Micro-OTDR stores its measurements in the EEPROM, just like any Digital Diagnostics Monitoring (DDM) data. These are accessed by the host Equipment via the I2C port using SNMP. When linked the data is stored and not refreshed (up to 15 reflections). The user can force a new measurement via the Tx Toggle command.
The data addresses in which DDM values are stored are defined in the Multiple Source Agreement (MSA). Conforming host equipment, which support DDM, must read the data from these addresses.
But the Micro-OTDR related data addresses are part of the Vendor-Specific section of the EEPROM, and are not routinely read by all MSA host equipment. Is there a way for MSA gear to read out the Micro-OTDR data?
The answer is a conditional Yes, but only if the host equipment always refreshes the Base ID Fields directly from the SFP EEPROM, and does not just save the data to cache memory at power-up.
Characteristics of the Alternate Micro-OTDR Readout:
- Values displayed are real-time.
- All reflections are counted, but only the distance to the farthest is displayed.
- Serves as indicator of Micro-OTDR status.
Mike Hartmann, VP of Business Development, Digital Marketing