In terms of the cable construction, OS1 is tight buffered while OS2 is loose tube. This determines they’ll be applied in different environment. OS1 single mode fiber is usually deployed in indoor applications such as schools, telecom exchanges and data center while OS2 single mode fiber is more appropriate for outdoor and universal loose tube solutions like street, underground and burial.
They’re different in maximum attenuations and transmission distance. The maximum attenuation and transmission distance for OS1 is 1.0db/km and 2km while for OS2 is 0.4db/km and 10km. And this determines that OS2 is much more expensive that OS1.
By default all our single mode fiber optic cable are OS2 fiber optic cable.