Whether an alarm will be reported at the local end when a 2M port does not transmit signals

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Whether an alarm will be reported at the local end when a 2M port does not transmit signals:
Generally, an alarm is detected and reported at the receive end. To determine whether the local 2M port is faulty, you are advised to check for alarms reported at the peer end (the receive end) or perform a self-loop.

Other related questions:
How to determine whether the peer end transmits numbers using DTMF signals or FSK signals?
Connect the phone to the AT0 line. If the calling number is displayed immediately a call comes in, DTMF signals are used. If the calling number is displayed after the first ring and before the second ring, FSK signals are used.

Reason why an OTU board still reports the R_LOS alarm when receiving optical signals normally
The possible cause is that alarm inversion is manually enabled. During network deployment, some alarms may be reported but are meaningless. For example, a LOS alarm is reported even though no cable is connected to a board on which a service has been provisioned. After alarm inversion is enabled, such an alarm can be not reported to prevent disturbance on maintenance engineers. Alarm inversion needs to be disabled after commissioning is complete.

Whether the VI port on the OBU board can report a LOS alarm
No, the VI port on the OBU board cannot report a LOS alarm. When logical fibers are created on the NMS, if no FIU board is configured at the local site and the multiplexed-wavelength optical signals of the peer site need to be connected to the OBU board at the local site, you are advised to connect the logical fiber to the IN port of the OBU board. In this way, the corresponding logical fiber will turn red in case of a fiber cut.

Reason why the RO port of the TN12OLP board does not output optical signals when the RI1 port has input optical signals, but outputs optical signals when the RI2 port has input optical signals
When no port configuration is configured on the TN12LOP board, the board receives optical signals through its RI2 port by default.

R_LOS alarm reported on an LWX2 board when its optical module normally receives optical signals
Question: One OSN 1800 NE is used for point-to-point networking at each of sites A and B. According to a hardware loopback test on the client-side and WDM-client optical ports of LWX2 boards at site A, an R_LOS alarm is reported on the NMS. Site B has the same issue. Analysis: 1. The receive optical power is lower than the lower limit. 2. The optical module is faulty. Root cause: None Answer: 1. Use an optical power meter to measure the receive optical power of the optical module. It is found that the receive optical power is normal. 2. Replace the relevant optical module. The alarm is cleared. 3. According to relevant documents, if the WDM side emits light forcibly when no scrambled optical signal is added to the client side, the emitted light is white light. If the client side emits light forcibly when no scrambled optical signal is received on the WDM side, the emitted light is also white light. The current alarm detection mechanism cannot extract valid information from the white light. Therefore, the R_LOS alarm is reported. 4. Change the client-side service access rate of site A to 622 Mbit/s and add STM-4 optical signals from an SDH NE to site A. Then the R_LOS alarm is cleared on the client side of site A and the R_LOS alarm on the corresponding WDM side of site B is also cleared. Perform a hardware loopback using a fiber on the client side of site B. Then the R_LOS alarm is cleared on the client side of site B and the R_LOS alarm on the corresponding WDM side of site A is also cleared. After the preceding steps, this issue is resolved. Suggestion and conclusion: If the WDM side of an LWX2 board emits light forcibly when no scrambled optical signal is added to the client side, the emitted light is white light. If the client side emits light forcibly when no scrambled optical signal is received on the WDM side, the emitted light is also white light. The current alarm detection mechanism cannot extract valid information from the white light. Therefore, the R_LOS alarm is reported.

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