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The OSN3500 SSN4SL64 optical interface board is a line single board that can be used on OptiX OSN series devices to realize the reception and transmission of STM-64 optical signals. Through this board, the SL64 sends the received optical signals to the crossover side through O/E conversion, while the electrical signals from the crossover side are sent out through E/O conversion.There are several functional versions of the SL64 board, and the functions provided by different functional versions are different, among which, the N2SL64 board has been discontinued.The single board supports functions and features such as receiving and transmitting 1 channel STM-64 optical signals, overhead processing, and so on.The single board consists of an optoelectronic conversion module, a MUX/DEMUX module, an SDH overhead processing module, a logic control module, and a power supply module.
The STM-64 signaling single board causes BERs in long distance projects due to sensitivity, fiber dispersion and distortion aspects. The impact of sensitivity, fiber dispersion and distortion on the system needs to be addressed in long-haul projects.
Produkte
OptiX OSN 3500
Failure Category
Error Code
Phenomenon Description
In an STM-64 link, the line board is SSN2SL6416 (V-64.2b, LC), and the related BPA (14) is also in use. The received optical power of the line board is -13.00dBm, and there is an associated DCU board in the link, but there are still BERs in the fiber.
Cause analysis
According to the specifications of SSN2SL6416 (V-64.2b, LC), the received optical power of the single board is within the normal range. Since a DCU single board is used, neither the received optical power nor the DCU is the cause of the problem. Comparison of the input and output power of the associated BPA reveals that the preamplifier power is -26.90 dBm, which is the cause of the problem.
The laser power of the signal from the STM-64 should not exceed -27.00 dBm, and when the laser power approaches -27.00 dBm, the laser distortion causes fiber optic miscoding.
Operation Steps
- Check the performance of the circuit board to see if the laser power is within the normal range (between the overload point and the sensitivity).
- Check and replace the DCU veneer board to see if the dispersion attenuation solves the problem.
- Check the performance of the relevant BPA. the input power to both ports of the V-64.2b veneer board should exceed -26dBm (1dB margin).
- The above steps reveal that sensitivity, dispersion or distortion is the cause of the problem.
- For distortion, check to see if there are also BERs on the other side, and if so, use a better fiber or BPA (e.g., BPA-17 instead of BPA-14).
- If there are no BERs on the other side, find out the cause of the excessive attenuation (1dB to 3dB error is normal for long-haul fibers), fiber optic connectors, fibers, or fiber splices can cause excessive attenuation.
Reference Information
STM-64 signals are very sensitive, long-haul projects require special attention to the sensitivity of the circuit board (using BPA), fiber dispersion (using DCU) and distortion (laser power must not be lower than -27dBm), checking every detail is necessary to eliminate BERs.
After selecting the correct veneer, the veneer needs to be tuned and configured. Single-board tuning and configuration consists of four parts: single-board hardware check, single-board configuration, single-board tuning and verification test.
The technical information in this chapter and the related SDH equipment troubleshooting procedures are provided by Shenzhen Optical Transmission Network Technology Co. Huawei SDH optical transmission equipment, SDH transmission equipment sales phone: 13430988088 Welcome to telephone consultation!
