Is It OK Mix Using OM2 OM3 OM4 Fiber Patch Cord

As we know, never mix single-mode and multi-mode fiber cable as it leads to high data loss. But is it possible to mix OM2 with OM3/OM4 fiber patch cord? They are the same diameter of 50µm, only have different bandwidth. But why not people mix use OM2 with OM3/OM4 fiber patch cables? There are several explanations in the below.

1.If you have OM2 in the walls, it makes no difference, and if you have a mixture of OM2/3/4 in the walls, it's probably a good idea to use (only) patch cords that match the highest grade fiber in the walls, as they won't hurt the lower grade runs, though it does run a risk of making the uninformed think that all the cables in the wall are OM4 when they are not. But the uninformed are rather hard to sort out in any case.

If you have OM3/4 in the walls, it's not a good idea, though it may "work" for some value of "work." But it's a terrible place to "save" a few bucks while wasting/degrading a few kilobucks of installed fiber plant.

2.The rating of a cable plant is determined by the lowest rating of any link in the cable plant. If you have OM4, and you use lower rated patch cords like OM2 or OM3, the rating of the cable plant is the lower rating of the patch cords. The same thing applies to copper cabling.

3.The main problem is that you are wasting your OM3/4 fiber introducing a physical bottleneck with OM2 segment. It's like the typical scenario where you have cat6 accross all the building and your users connect their workstations with cat5e.

In summary, It will work? In my experience, it works on most of the scenarios. Is it a good idea? Totally no, do it only if you have no other options.

OK, now we know why we don't mix using the OM2 OM3 OM4 fiber patch cords.