Multimode Patch Cord Guide

A multimode patch cord connects two pieces of multimode equipment over a short distance, and its performance depends on the fiber grade inside it more than on any other single factor. Multimode fiber comes in grades, and the grade decides how far a given speed can run. The two grades in current use are OM3 and OM4, and the difference between them is the bandwidth of the fiber: OM4 carries a higher bandwidth than OM3, which translates directly into longer reach at the same speed. This guide covers multimode patch cords at category level, including the grade question.

The grade question matters because reach figures for multimode modules are stated against a grade. The published SFP+ SR model on this site, for example, states a 300m reach against a 2000MHz/km fiber, which is the OM4 class of performance. Over a lower-grade plant, the same module reaches less far. A buyer who knows the installed grade can plan on the published figure; a buyer who does not know it should find out before ordering, because the grade is the difference between a link that works at full distance and one that falls short.

OM3 and OM4 differ in construction as well as in bandwidth. OM4 fiber is manufactured to tighter tolerances, which reduces the modal dispersion that limits multimode distance, and it is usually identified by an aqua jacket, while OM3 is also aqua in many installations, so jacket colour alone does not distinguish them. The printing on the jacket is the reliable evidence: it states the grade. A site that is unsure of its installed grade should read the jacket printing or the installation records before ordering, and state the grade during the inquiry.

Connector types for multimode patch cords follow the same pattern as for single-mode cords: LC is the default for modern equipment, SC appears in older plant, and ST appears in the oldest installations. Mixed cords, with different connectors at each end, are standard products for the common situation where new equipment meets old plant. The handling rules are the same as for single-mode cords — caps on until connection, clean end faces, no touching, no tight bends — though the wider multimode core is slightly more forgiving of dirt and misalignment. Slightly more forgiving does not mean immune, and dirty multimode connectors still cause failed links.

This guide states patch cord practice at category level. No patch cord model, length option, loss figure or connector specification is stated here as a product claim, because none has been published for a patch cord product. Before ordering, confirm quantity, price and delivery time during the inquiry. Certificates are available upon request.