Q: Can you use OM3 or OM4 "in place" of OM1?
A: It depends. OM1 fiber optic cable has a glass core that is 62.5 microns in diameter. OM3 and OM4 utilize a core that is 50 microns in diameter. If you are removing OM1 cable and installing OM3 or OM4, then these can be used. They will work with the technology that is supported by OM1. However, you cannot mix and match OM1 with OM3 and OM4 due to the difference in the core sizes. It would be like mating up a garden hose with a fire hose. It may work in one direction, but it won’t work in the other.