April 22, 2023

Five common faults in optical transceivers are solved by experts in this way.

An optical transceiver is ultimate equipment for transmitting an optical signal.

The role of optical transceiver in security is mainly to play transmission role of optical transceiver itself. The function of optical transceiver is to convert some signals with relatively short transmission distances into signals with relatively long transmission distances for transmission. The main function is to increase transmission distance and reduce monitoring costs (multi-channel video signals can be fiber optic transmission).

Five common faults in optical transceivers are solved by experts in this way.

Optical transceivers may also have some malfunctions during use. The following are common faults and solutions for optical transceivers. Find out how experts fix them.

No video signal

1. Check if power of each device is normal.

2. Check if video indicator of corresponding channel is lit on receiving side,

If indicator is on (on, it means there is video output on channel at that time). Then check if video cable is well connected between receiving end and terminal equipment such as a monitor or DVR, and if video interface connection is loose or if there is a false weld.

The video LED on receiving side is off, check if video LED on corresponding channel on front end is on. (It is recommended to re-enable optical receiver to ensure video synchronization)

If above methods cannot resolve problem and there are similar devices, you can use replacement test method (requires device to be interchangeable), that is, connect optical fiber to a normally working receiver. at other end or replace transmitter at far end Pinpoint faulty equipment.

Interference snowflakes appear on screen

1. Check for excessive bending of pigtail (especially with multi-mode transmission, care should be taken to ensure that pigtail is stretched and not bent excessively).

2. Check if connection between optical port and terminal box flange is secure, if flange core is damaged, etc.

3. If optical port and pigtail are too dirty, they should be cleaned with alcohol and cotton and then inserted after drying.

4. When laying line, video transmission cable should try to use a 75-5 cable with good shielding and good transmission quality, and should try to avoid AC lines and other objects that may cause electromagnetic interference.

Missing control signal or abnormal signal

1. Refer to data port definition in product manual to check if data cable connection is correct, secure and reliable. Especially if positive and negative poles of control line are reversed.

2. Check if control data signal format sent by control device (computer, keyboard or DVR, etc.) matches data format supported by optical transceiver, and if baud rate exceeds range supported by control device. optical transceiver (0-100Kbps).

3. Refer to data port definition in product manual to check if data cable connection is correct, secure and reliable. Especially if you putThe left and negative poles of control line are reversed.

Disappears input of a specific branch

1. Review alarm information of optical transceiver and find that 2/8 direction multiplex board is red, and at same time, control alarm board indicator I1 is on, indicating that branch 2M1 of board is faulty.

2. To judge whether it is a failure of optical transceiver tap unit or a failure of input interface from software-controlled computer room to optical transceiver, there are two methods to determine: first is to self-close input port of tap If fault persists, then this is fault of tap The unit is faulty diagram, if fault disappears, then it is a fault on software-controlled equipment side of room. Second, use transmission performance analyzer for online monitoring at input port of branch. If "code input is normal", it means that optical transceiver's branch unit is faulty, if "code input is interrupted, this is computer room side of program control. For example, use first method to decide that this is a bug on software-controlled computer room side.

3. Further online testing at Point B of Digital Distribution Rack using a Transmission Analyzer shows a "Code Entry Interrupt", indicating a fault between switching unit and input port of Digital Distribution Rack.

4. Notify computer room staff immediately to monitor status of switch. Found that signal light on Qiangbai circuit relay board is on, replace board immediately, alarm will disappear and circuit will unlock.

This error is caused by digital relay block associated with switch not sending an output signal. These kinds of faults also often occur at junction of cable between switch and optical transceiver. We urgently need to run a circuit with a spare line.

Optical reception failure

1. View alarm information of both optical transceivers

When observing optical transceiver, it was found that red and yellow lights of signal lamp of light board blink alternately, then light up, then go out, lights of control and warning panel I7 and I8 are on. These messages indicate that Dali received code messages 10-3 and 10-6; watching Qiang Baiguang relay, there is no warning message. This indicates that this is a unidirectional optical path failure.

2. There are 3 ways to determine if optical board or optical cable is at fault: a. Use a spare board to replace optical boards of both sides.cable; B. Use an optical power meter to measure emitted and received light power respectively, and can also determine whether it is error of optical board or optical cable. C. Using a pigtail + optical attenuator to transmit and receive its own loop on optical board can also determine failure of optical board or optical cable. I use first method to decide that it is an optical cable failure.

3. If there is a spare fiber strand in optical cable, you can try to replace it; if there is no spare fiber core, you need to carefully evaluate whether it is a pigtail or an outdoor fiber cable? core of optical cable is not good, and it is not broken at all, outdoor cable is not likely to break, it is better to check pigtail first.