April 30, 2023

Six Common Fiber Optic Transceiver Faults, All Fixed in Three Minutes

A fiber optic transceiver is an Ethernet media conversion unit that exchanges short-distance twisted-pair electrical signals with long-distance optical signals. In many places, it is also called a fiber optic converter.

Six Common Fiber Optic Transceiver Faults, All Fixed in Three Minutes

Fiber optic transceivers are commonly used in real network environments where Ethernet cables cannot be covered, and optical fibers must be used to increase transmission distance, and are usually located at access layer of broadband metropolitan networks, for example: high-definition high-definition video monitoring for security when transmitting images, and also played a huge role in connecting last mile of fiber to city network and external network.

Fiber optic transceivers will encounter various problems during use. Today, I will share with you common faults and solutions for fiber optic transceivers.

1. Link indicator is off

(1), check if optical fiber is not damaged;

(2). Check if loss in fiber optic line is too high, exceeding receiving range of equipment;

(3) Check if fiber interface is connected correctly, local TX is connected to remote RX, and remote TX is connected to local RX.

(4) Check whether fiber optic connector is correctly inserted into device interface, whether jumper type matches device interface, whether device type matches optical fiber, and whether transmission length of device matches distance.

2. Circuit link indicator off

(1), check if network cable is damaged;

(2), check that connection type matches: use crossover cables for NICs and routers, and use straight cables for switches, hubs, and other devices;

(3) Check if device's baud rate matches.

Six Common Fiber Optic Transceiver Faults, All Fixed in Three Minutes
3. Severe network packet loss

(1), electrical port of transceiver does not match duplex mode of network device interface or device interfaces at both ends;

(2), there is a problem with twisted pair and RJ-45 head, check it;

(3), fiber connection problem, whether jumper is aligned with device interface, whether pigtail matches type of jumper and connector, etc.;

(4) Whether fiber loss exceeds sensitivity of equipment.

4. After connecting fiber optic transceiver, two ends can not communicate

(1), optical fiber is reversed, and optical fiber connected to TX and RX is reversed;

(2), RJ45 interface is not properly connected to external device (pay attention to direct connection and splicing), and fiber optic interface (ceramic ferrule) does not match. This fault is mainly reflected in 100M transceiver with a photoelectric mutual control function such as APC. If handpiece pigtail is connected to PC handpiece transceiver, it will not be able to communicate normally, but it will not affect connection of non-optical mutual control transceiver.

Six Common Fiber Optic Transceiver Faults, All Fixed in Three Minutes
5. The phenomenon of switching on and off

(1) The attenuation of optical path may be too high. At this time, an optical power meter can be used to measure optical power at receiving end. If it is close to reception sensitivity range, it can basically be regarded as an optical path failure in range of 1-2 dB;

(2) The switch connected to transceiver may be defective. At this time, replace switch with PC, that is, two transceivers are directly connected to PC, and both ends are in PING mode. This is considered to be switch is defective;

(3) The transceiver may be defective. At this time, you can connect both ends of transceiver to PC (do not go through switch). After both ends have no problems with PING, transfer a large file (100M) from one end to other. Above, pay attention to its speed, if speed is very low (file transfer below 200M takes more than 15 minutes), it can be basically regarded as transceiver failure

6. After crash and restart, it will return to normal

This phenomenon is usually caused by a switch. The switch performs CRC error detection and length checking on all received data, discards invalid packets, and sends correct packets.

But in this process, some erroneous packets cannot be detected by CRC error detection and length checking. Such packets will not be sent or discarded in process, but accumulated in a dynamic buffer (buffer), it can never be sent. When buffer is full, this will cause switch to fail. Because restarting transceiver or restarting switch at this time can restore normal communication.