Common Troubleshooting for Telephone Optical Terminals

Device fails to power on

1. Check whether the power cable is connected correctly.
2. Check whether the voltage is within the allowable operating range of the device.
3. Check whether the power is within the operating range.
   2M link failure
4. First check whether the interface impedance matches, ensuring that the impedance of the connected device is consistent with that of the device itself;
5. Each E1 channel has an indicator light. When the indicator is lit, it indicates a signal loss on the corresponding E1 channel. Under normal operation, the indicator should be off. If the indicator is lit, check whether the 2M cable and BNC connector of the device's E1 port are in good contact.
6. Next, check whether the device itself operates properly. The test method is to use a 2M cable to loop the transmit and receive ports of one device together (i.e., E1 loopback). If the LOS red indicator goes off, the E1 port of the device is normal. Both ends of the devices should be checked in this manner.
   Note: The loopback test can only be performed when the device clock mode is set to master clock.
   Optical loss alarm
   When the optical alarm indicator (NOPO) is lit, it indicates that the optical fiber connection has not been established.
   1. Physical fiber condition:
7. First check whether the fiber is in good contact with the device. Replug the fiber connectors at both ends into the device optical ports to ensure good contact;
8. Check whether the fiber is intact;
   2. Device self-test: Next, check whether the device itself operates properly. The test method is to use a fiber to connect the receive port and transmit port of one device together (i.e., optical loopback). If the red indicator goes off, the optical port of the device is normal.
   3. When single-fiber is used:
9. Check whether the optical modules are normal: typically, one end uses a 1310nm optical module and the other end uses a 1550nm optical module;
10. Check whether the fiber distance meets the requirements, such as 20Km, 40Km, 60Km, etc.
    High bit error rate on E1 port
11. Check whether the interface impedance is correct.
12. Check whether the grounding is correct.
    Service failure
    Telephone service failure
13. Physical connection correctness: Check whether the telephone output interface corresponds to the service interface, whether the output telephone interface is reliable, and whether the RJ45 connector is crimped correctly and properly.
14. Device settings: Confirm whether the DIP switches on the panel for the central office end and remote end are set correctly.
15. Confirm whether the device is operating normally.
    Ethernet failure
16. First check whether the network cable connection method is correct.
17. Check whether the RJ45 crimping meets the requirements for Ethernet cable crimping.
18. Check whether the configurations of the PCs on both sides are correct, whether they are on the same subnet, and whether the IP addresses, workgroup, gateway, etc., on both ends are correctly configured.