Telephone Optical Terminal Installation, Maintenance, and Common Fault Troubleshooting Methods
1. Equipment Installation
1.1 Equipment Installation Precautions
【This series of equipment contains precision components. Please handle with care and avoid severe vibration to prevent affecting equipment performance. If you find the equipment damaged or any parts missing during transportation, please contact our after-sales service department, and we will resolve the issue promptly.】
★ Remove the unit and accessories from the packaging. When opening, pay attention to the orientation of the carton and ensure it is upright to avoid losing the accessory kit.
★ Check the equipment and accessories against the packing list. Please inspect carefully and verify they match the packing list.
★ Keep the network configuration diagram in a safe place for reference during installation and maintenance.
★ Install the unit on a 19-inch standard rack or cabinet. Tighten the screws on the front panel when the equipment is commissioned. If necessary, install a support tray beneath the unit to bear its weight.
★ Do not block the ventilation holes on the top, bottom, left, or right sides of the equipment.
★ Prevent foreign objects from falling into the chassis. If dust accumulates on the equipment, wipe it off with a soft cloth.
★ Before powering on, use a multimeter to verify that the voltage at the power terminal is -48V±10% with correct polarity, and that the protective ground is properly connected to the equipment room ground.
1.2 Equipment Installation and Cable Connection
- Distinguish between the central office (CO) and remote units: the CO unit connects to the switch, while the remote unit connects to the user's ordinary telephone. Do not swap the installation locations of the CO and remote units, otherwise services will not work.
2) When installing, first place the equipment onto the mounting tray at the designated position in the cabinet, aligning the positioning holes of the mounting ears with those of the cabinet rack. Ensure the unit slides in smoothly and straight. If resistance is encountered, check whether the tray or the unit is deformed. Do not force the unit in, as this may damage the equipment.
3) Push the unit fully into the cabinet. After aligning the positioning holes of the mounting ears with those of the cabinet mounting tray, tighten the cabinet screws to securely fix the unit to the cabinet.
4) Power cable connection:
The standard power configuration for this equipment is DC-48V or AC~220V. Before connecting power, measure the voltage and power capacity of the power source to ensure they are within the equipment's requirements:
a) -48V power supply: -48V±10%;
b) AC220V power supply: standard AC220V±20%, 50Hz;
5) Before applying power, check that the equipment's power switch is set to OFF. If not, set it to OFF.
6) Verify that the -48V power cable, GND (working ground) cable, and PGND (protective ground) cable are connected correctly and that polarity is not reversed. Note: the working ground and protective ground of the equipment are separate, and the protective ground is connected to the chassis. If necessary, the working ground and protective ground can be connected together at the backplane power connection point. Be sure to resolve the common grounding issue.
7) Grounding technical recommendations: The equipment chassis should be connected to the protective ground. If the central office provides separate working ground and protective ground, connect the equipment's working ground and protective ground to the corresponding grounding copper bars. If only one grounding copper bar is provided, the working ground and protective ground may be jointly grounded, provided that the grounding resistance meets the requirement of no greater than 4Ω for the DC working ground.
The GND (power working ground) and PGND (protective ground) must be properly connected. Only after confirming that the power cables are correctly connected should power be applied to the equipment. If any abnormality occurs after power-on, power off immediately and inspect and resolve the issue.
The -48V working power cable is red, the GND (working ground) cable is black, and the PGND (protective ground) cable is yellow-green or white. Distinguish them carefully during connection and never reverse the power polarity.
The approximate location of the power terminal block and related warning labels are shown in the figure below:
Meaning of the numeric labels:
1: Reminds installers to pay attention to AC220V power safety during installation;
2: Reminds installers to properly connect the protective ground during installation; the protective ground wire is yellow-green;
3: Reminds installers to measure the potential difference between the shell of the 2M (E1) interface and the shell of the cable BNC connector before connecting the 2M cable to the equipment. Only when there is no potential difference may the 2M cable be connected to the equipment.
8) Pigtail connection: Remove the dust caps from both ends of the pigtail, gently insert the connector into the optical port, and then tighten the fixing nut. Connect one end of the pigtail to TX (optical transmit port) and the other end to RX (optical receive port).
Note: When connecting optical fibers, never look directly into the optical port with your eyes to avoid eye injury from the optical signal.
9) 2M cable connection: Connect one end of the 2M cable to E1 IN (2M input interface) and the other end to E1 OUT (2M output interface). Before connecting the 2M cable to the local unit, first connect the E1 interface of the remote unit to the 2M cable, then power on both the remote and local units. Use a multimeter to measure the potential difference between the shell of the coaxial cable BNC connector and the shell of the local unit's 2M interface. If the potential difference is zero, the grounding meets the requirements. If the potential difference is not zero, the grounding does not meet the requirements. Check the equipment grounding, ensure proper grounding, and then connect the 2M cable and activate the service.
2. Service Activation
2.1 Telephone Service Activation
- The connection sequence between devices is as follows:
At the central office, the equipment connects to the switch; at the remote end, the equipment connects to an ordinary telephone. The CO unit and remote unit are interconnected via coaxial cable (IDM-30 Integrated Service Transmission Unit) or optical fiber cable (IDM-30N Integrated Service Transmission Unit).
2) After connecting all service cables according to the above method, power on the equipment and observe the indicator lights. Under normal operating conditions, the power indicator (POW) is lit, and the LED31 indicator is lit.
3) Connect the ordinary telephone at the remote end to the service interface of the remote unit, lift the handset and dial. If communication is established normally after dialing, the telephone service is activated.
2.2 Ethernet Service Activation
- The Ethernet service applies to the IDM-30N Integrated Service Transmission Unit. To activate the Ethernet service, connect one end of the Ethernet cable to the equipment's Ethernet interface and the other end to a PC.
2) After connecting the Ethernet cable, correctly configure the PC's IP address, gateway, and subnet mask.
3) Connect to the network, open an IE browser, and enter the correct URL. If the webpage loads normally, the Ethernet service is activated.
3. Equipment Maintenance
- Cleaning and maintenance: Regularly check the equipment chassis for dust or debris and clean it, keeping the ventilation holes unobstructed.
2) Power supply inspection: Regularly measure the equipment's power supply to ensure the voltage is normal.
3) Line inspection:
a. Regularly inspect the equipment's power lines and service lines.
b. Ensure that the power cables are firmly connected to the power terminal block without looseness, that the entire power connection circuit and equipment grounding are in good condition, and that the lines are free from damage and leakage.
c. Ensure that service cables are properly connected to the corresponding service interfaces.
4. Common Fault Troubleshooting
4.1 Equipment Cannot Be Powered On
- Check whether the power cable is connected correctly.
2) Check whether the voltage is within the equipment's allowable operating range.
3) Check whether the power capacity is within the operating range.
4.2 2M Link Failure
- First, check whether the interface impedance matches. Ensure that the impedance of the connected equipment is consistent with that of the local equipment.
2) Each E1 channel has an indicator light. When the indicator is lit, it indicates a loss of signal on the corresponding E1. Under normal operation, the indicator should be off. If the indicator is lit, check whether the 2M cable and BNC connector of the equipment's E1 interface are making good contact.
3) Next, check whether the equipment itself is functioning properly. The test method is to use a 2M cable to loop the transmit and receive ports of one unit together (i.e., E1 loopback). If the LOS red indicator goes off, the E1 port of this unit is normal. Both ends should be tested in this manner.
Note: Loopback testing can only be performed when the equipment clock mode is set to master clock.
4.3 Optical Loss Alarm
When the optical alarm indicator (NOP) is lit, it indicates that no optical link has been established.
1. Optical fiber physical condition:
1) First, check whether the optical fiber is making good contact with the equipment. Reconnect the fiber connectors at both ends to the optical ports to ensure good contact.
2) Check whether the optical fiber itself is normal.
2. Equipment self-test: Next, check whether the equipment itself is functioning properly. The test method is to use one optical fiber to connect the transmit port of a unit to its receive port (i.e., optical loopback). If the red indicator goes off, the optical port of this unit is normal. Set the equipment clock mode to master clock before performing the loopback test. After the test, restore the clock DIP switch to the factory default state.
3. When a single-fiber configuration is used:
First, the optical modules at the two ends are different:
1) Check whether the optical modules are normal: typically, one end uses a 1310nm optical module and the other end uses a 1550nm optical module.
2) Check whether the fiber distance meets the requirements: e.g., 20Km, 40Km, 60Km, etc.
4.4 High Bit Error Rate on E1 Output
- Check whether the interface impedance is correct.
2) Check whether the grounding is correct.
4.5 Service Failure
4.5.1 Telephone Service Failure
1) 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 to specification.
2) Equipment settings: Confirm that the DIP switches on the panel for the CO and remote units are set correctly.
3) Confirm that the equipment is functioning properly.
4.5.2 Ethernet Failure
1) First, check whether the network cable connection method is correct.
2) Check whether the RJ-45 crimping meets the requirements for Ethernet cable termination.
3) Check whether the PC configurations on both sides are correct, whether they are on the same subnet, and whether the IP addresses, workgroup, gateway, etc., are correctly configured on both ends.