Description of the problem

We know that the light-emitting and light-receiving ranges of Huawei OSN3500 devices SSN4SL64 V-64.2b and SSN1SL64 L-64.2b veneers themselves are the same, except that the veneer of V64.2b is a fixed-wavelength veneer of 1550.12, which can be used together with Huawei's BPA veneer (the BPA module used in the SDH system is different from that of the wavelength-division system, and light of 1550.12 wavelength can be amplified normally), while the veneer of L64.2b is not fixed-wavelength so it can only be used with BA. (The BPA module used in SDH system is different from WDM system, it can only amplify the light of 1550.12 wavelength normally), while the single board of L64.2b is not fixed wavelength, so it can only be used with BA. You may think, V64.2b single board does not work with the PA should be used with L64.2b the same effect, but in fact is not the same effect, V64.2b single board can replace the L64.2b single board? Let's analyze further.

Processing

Since the hardware description does not introduce the dispersion tolerance of the single board, you may not have noticed that the dispersion tolerance of the L64.2b single board is 1600ps/nm, so he does not need to add the dispersion compensation module with the BA to transmit 80KM, whereas the dispersion tolerance of the V64.2b is 800ps/nm, so it needs to add the BA and PA, and cooperate with the dispersion compensation module of the 80KM in order to transmit 80 to 120km. In this way, when the distance between two points is 40 to 80KM, using V64.2b single board to replace L64.2b single board, because the previous L64.2b single board is not added dispersion compensation module, so the range of receiving light can certainly meet, but may be due to the dispersion undercompensated resulting in error codes, so V64.2b single board can not be a direct replacement for the L64.2b single board, you need to consider the actual dispersion of the line, usually the dispersion of the GNSS is not enough, so it is necessary to consider the actual dispersion of the line. The actual dispersion of the line needs to be considered, usually the dispersion of G.652 fiber optic cable is 20 ps.nm/km, and the dispersion of G.655 fiber optic cable is 7 ps.nm/km.

Recommendations and Summary

1、It is not the case that the dispersion tolerance of the optical plate with a longer distance is also larger;

2, for the Huawei OSN3500 BPA module used in the SDH system, only 1550.12 fixed-wavelength light can be amplified normally, and not all optical boards can be used with BA2;

3. It is recommended that the description of the dispersion tolerance of the single board be added to the product manual.