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With the development of the urban process and the complexity of the security environment, more and more fiber optic technology is used to transmit images, sounds, data and other information in the security monitoring project. The key equipment of the optical fiber transmission system--digital video optical transceiver is favored by the majority of users. Therefore, it is urgent to be familiar with the optical transceiver to cope with possible problems. The following is a brief introduction to the problems in the use of optical transceivers: 
1. Generation of transient interference: Transient interference is generated by large inductive loads, such as switching of motors, transformers, relays, etc., and during the occurrence of lightning, it often invades the optical transceiver by electrostatic induction.
2, the hazard of transient interference: due to its high frequency of interference, short duration, large amplitude of interference (hundreds of thousands of volts), it can burn out the key parts of the RS-485 interface chip and main chip of the optical transceiver, but does not stay Traces, especially during the summer thunderstorm season, have a great impact on the destructive power, making users, businesses and manufacturers very nerve-wracking.
3. Countermeasures: Although optical transceiver manufacturers use various protection methods such as bypass (self-recovery diode), absorption (bidirectional suppression diode, etc.), isolation (optocoupler isolation), they cannot completely eliminate transients. The damage caused by interference, the RS-485 interface is damaged frequently, causing great pressure on users and manufacturers.
Second, the video optical transceiver optical transmission problem:
In the security monitoring project, most of the optical cables are laid by the users themselves, generally G652 single-mode optical fibers. Since the coverage of the system is generally small, the optical link loss of the device is very rich with the standard (≤20KM). Therefore, the optical transceiver does not have excessive requirements for optical path loss, but users often encounter no image, image jitter, and image quality. Problems such as poor, when most of the problems are on the pigtails, jumpers or adapters at both ends of the light path, and rarely related to the trunk light path.
Common problems are:
1. The fiber optic active connector is inserted incorrectly;
2. The fiber optic active connector core (ceramic tube) is contaminated.
The solution is:
1. Reinsert the active connector or swap the fiber jumper;
2. Wipe the plug with 99.9% absolute ethanol and the core of the socket;
3. Check the camera video cable with a multimeter to determine if there is any video signal.
The light path problem is often caused by insufficient planning during the laying of the previous cable.
Third, the data interface of the optical transceiver is stuck:
In order to meet the needs of security monitoring, all kinds of equipment (matrix, hard record, decoder) provide RS-485 data interface. The advantage of this format data interface is long transmission distance, strong load capacity and can form four. Line full-duplex communication bus, any two devices on the line can achieve two-way communication, while the four-wire RS-422 bus can only achieve two-way communication between the master and slave, but not between the slaves. Its shortcoming is that there is an enabling end, which is in a three-state form, which brings instability and even "catch" to the communication. If there is no communication (out of control), you should look up the reasons from the following aspects:
1. Detect whether there is any control signal. Use the multimeter AC 10V test controller (matrix, hard record, etc.) to output the RS-485 port to see if it has control signal output.
2. Determine whether the RS-485 interface of the optical transceiver is normal. If the UA-B voltage is zero, it is considered abnormal.
The cloud station can't be controlled. This phenomenon is caused by two reasons: a) RS-485 port A, B-connected; b) system impedance is seriously mismatched.
Fourth, the video optical transceiver's switching failure signal is a TTL level pulse train, it can control the lights, alarms, relays, etc., the load capacity of the switch interface is measured by the magnitude of the current, such as EW series The switching capacity of the optical transceiver is ≤1.5A.
1. The CNV series optical transceiver switch interface supports the normally open button, and the normally open and normally closed modes support:
2. The switch quantity interface cannot be directly used in parallel. If necessary, it can only be accessed through the distribution circuit.
3. Some customers use the RS-485 bus to transmit the switch quantity. According to our practical experience, this method is not advisable. It often occurs when the work is working for a period of time (such as 3~4 days). Defects in the switching of RS-485 converters may be the problem.
Connection: Flange DIN PN10, ANSI CL150, JIS10K; socket DIN, ANSI, JIS, CNS, BS; Thread BSPT, NPT.
Body Material:PVC-U
Seal material:EPDM
Seat Material:PTFE; PP
Design pressure:1.0Mpa(PN10 bar)
Video optical transceiver failure and solution
[ Huaqiang Security Network News ] There are many kinds of faults in video optical transceivers. It is necessary to classify the faults of optical transceivers, check the faults step by step, and finally lock the faulty equipment to solve the problem quickly. Zhongwei Guanhua proposed analysis and solutions for the four major failures of video optical transceivers. I. Harm and Solution of Transient Interference of Optical Transceiver This problem is common in the remote optical signal transmission of optical transceivers, and it is also harmful.