How to identify fiber optic cable is multi-mode or single mode?

 
The first is a relatively simple way, for indoor optical fiber, can be single-mode fiber andmultimode fiber to identify the external color, single-mode optical fiber / cable is yellow, while the multimode is red. Including fiber optic patch cords and pigtails are the sameidentification method.

For outdoor fiber / cable, can generally be identified by the model code, the cable jacket hasa string of characters, such as GYXTW-4-A1a, the last paragraph beginning with A on behalf of a multi-mode fiber, the B represents the beginning of a multi-mode fiber, slightly more detail, said, A1a behalf 50/125 multimode fiber specifications, A1b specifications on behalf of 62.5/125 multimode fiber, B1.1 on behalf of non-dispersion shifted single-mode fiber, and so on.

If this approach can not identify a single-mode fiber or multimode fiber, it is only through aspecial device to identify, as fiber splicing machine, it will automatically identify the single mode or multimode, single mode will show SM, multi-mode will show MM.

Of course, on the other hand say, single-mode fiber