How to troubleshoot installation, maintenance, and common faults of Telephone Optical Terminal?

1. Equipment Installation

　　1.1 Precautions for Equipment Installation

【This series of equipment contains precision components. Please handle with care and avoid severe vibration to prevent affecting equipment performance. If you find any parts damaged or missing during transportation, please notify the company's after-sales service department, and we will resolve the issue promptly.】

　　★ Remove the unit and accessories from the packaging. Pay attention to the orientation of the packaging box when opening, ensuring the front side faces upward 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 in a cabinet. Tighten the screws on the front panel when the equipment is commissioned. If necessary, install a support tray underneath the equipment to bear its weight.

　　★ Do not block the ventilation holes on the top, bottom, left, or right sides of the equipment.

　　★ Ensure no foreign matter falls into the chassis. If dust accumulates on the equipment, wipe it with a soft cloth.

　　★ Before powering on, use a multimeter to measure whether the voltage at the power terminal is -48V±10% and whether the polarity is correct. Verify that the protective ground is properly connected to the equipment room ground.
1.2 Equipment Installation and Cable Connection

1. Distinguish between the local (CO) and remote (RT) units: the local unit connects to the switch, while the remote unit connects to the user's ordinary telephone. Do not swap the installation locations of the local and remote units, otherwise services will not work!

　　2) During installation, first place the equipment onto the mounting tray of the rack bracket at the designated position, aligning the positioning holes of the mounting ears with those of the rack frame. Ensure the insertion is straight and smooth. If there is resistance, check whether the tray or equipment is deformed. Do not force the equipment in, as this may damage it.

　　3) Push the equipment fully into the cabinet. After aligning the positioning holes of the mounting ears with those of the rack mounting bracket, tighten the cabinet screws to securely fix the equipment to the rack.

　　4) Power cable connection:

　　The standard power configuration of the 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 whether the equipment's power switch is set to OFF. If not, set it to OFF;

　　6) Check whether the -48V power cable, GND (working ground) cable, and PGND (protective ground) cable are connected correctly and whether the polarity is 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 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, and the grounding resistance should meet the requirement that the DC working ground resistance does not exceed 4Ω.

　　The GND (power working ground) and PGND (protective ground) of the equipment must be properly connected. Only after confirming the power cable connections are correct should the equipment be powered on. 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 equipment 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 cable 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 can the 2M cable be connected to the equipment;

　　8) Pigtail connection: remove the dust caps from both ends of the pigtail, gently insert the pigtail connector into the optical interface, and then tighten the fixing nut. Connect one end of the pigtail to TX (optical transmit interface) and the other end to RX (optical receive interface).

　　Note: never look directly into the optical interface with your eyes during fiber connection, as the optical signal may damage your eyes!

　　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 equipment, first connect the E1 interface of the remote equipment to the 2M cable, then power on both the remote and local equipment. Use a multimeter to measure the potential difference between the shell of the coaxial cable BNC connector and the shell of the local equipment'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

1. The connection sequence between equipment is as follows:

　　At the local end, the equipment connects to the switch; at the remote end, the equipment connects to an ordinary telephone. The local and remote equipment are interconnected via coaxial cable (IDM-30 Integrated Service Transmission Equipment) or optical fiber cable (IDM-30N Integrated Service Transmission Equipment).

　　2) After connecting all service cables according to the above connection 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 equipment, go off-hook and dial. If communication is normal after off-hook and dialing, the telephone service is activated.
2.2 Ethernet Service Activation

1. The Ethernet service applies to the IDM-30N Integrated Service Transmission Equipment. 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 network connection works normally, the Ethernet service is activated.

3. Equipment Maintenance

1. Cleaning and upkeep: periodically check the equipment chassis for dust or debris and clean it, keeping the ventilation holes unobstructed.

　　2) Power supply inspection: periodically measure the equipment's power supply to ensure the voltage is normal.

　　3) Line inspection:

　　a. Periodically inspect the equipment's power lines and service lines

　　b. Ensure the equipment's power cables are firmly connected to the power terminal block without looseness, and ensure the entire power connection circuit and equipment grounding are in good condition, with no damage or leakage in the lines;

　　c. Ensure the service cables are properly connected to the corresponding service interfaces.

　4. Common Fault Troubleshooting

　　4.1 Equipment Cannot Be Powered On

1. 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

1. First check whether the interface impedance matches. Ensure 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 signal loss 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 operates normally. The test method is to use a 2M cable to loop back the transmit and receive of one equipment (i.e., E1 loopback). If the LOS red indicator goes off, the local equipment's E1 interface is normal. Both ends should be checked 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 the optical fiber link has not been established.

　　1. Optical fiber physical inspection:

　　1) First check whether the fiber is making good contact with the equipment. Re-insert and reconnect the fiber connectors at both ends to the equipment's optical ports to ensure good contact;

　　2) Check whether the fiber itself is normal.

　　2. Equipment self-test: next, check whether the equipment itself operates normally. The test method is: use one fiber to connect the receive end and transmit end of one equipment (i.e., optical loopback). If the red indicator goes off, the local equipment's optical port 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 the fiber is single-fiber:

　　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 at E1 Output

1. 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 crimping is correct and qualified.

　　2) Equipment settings: confirm whether the DIP switches on the front panel for local and remote ends are set correctly.

　　3) Confirm whether the equipment is operating normally.

　　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 Ethernet cable crimping requirements.

　　3) Check whether the PC configurations on both sides are correct, whether they are on the same subnet, and correctly configure the IP addresses, workgroup, gateway, etc. on both ends.