The major differences are the number port of the fiber interface and the fiber-optic distance. The difference is as table below.
Model Name |
ISW-511 |
ISW-511S15 |
ISW-621 |
ISW-621S15 |
100Base-FX Fiber |
1 |
2 |
||
Fiber Distance |
2 km |
15 km |
2 km |
15km |
Fiber Mode |
Multi-Mode |
Single-Mode |
Multi-Mode |
Single-Mode |