Choosing a Pre-Terminated Fiber Optic Assembly


Choosing a fiber cable for your installation can sometimes be confusing given all of the choices. In this article, we will attempt to clear up some of the confusion. Basically there are two attributes that you will need to consider and those are “cable material and construction” and “fiber type”. First we will talk about cable material and construction. The types of material and construction include the following:

>Cable Material and Construction

Indoor Plenum

Use this for all indoor installations. The cable can be run directly in all indoor applications. Installation in conduit or innerduct is not required but does offer additional security for the possibility of the cable from being cut. Most installations do not use conduit of innerduct. A cable rated for plenum installation will have low-smoke characteristics as defined by the NFPA (National Fire Protection Agency).


Outdoor cables are filled with a water blocking jell and are rated for all outdoor applications except for "direct bury". This cable is suitable for underground installation in conduit, overhead lashed to a guy wire, or secured to a building or other permanent outdoor structure. The drawback of the jell-filled cable is that it is mandated at a maximum of 50 feet run indoors due to fire-code regulations.


Please note that the only difference between outdoor (jell-filled) and direct bury cable is that the latter has an added overall metallic sheath which gives it protection from rodents. If you require a direct bury cable, please contact sales for a quote.



Indoor/Outdoor cables are approved for use in underground conduits, even if the possibility of water infiltration exists. Indoor/Outdoor cables are not recommended for aerial installations. The advantage of using Indoor/Outdoor over standard Outdoor cable is that it does not have the 50 foot restriction for indoor installation that standard outdoor cable has. This cable has an overall PVC sheath and is not rated for plenum spaces.

Interlock Armor Indoor Plenum

This cable has all of the attributes of Indoor Plenum cable with the additional benefit of the armor which protects it from accidental cutting.

Interlock Armor Indoor/Outdoor Plenum

This cable has all of the attributes of Indoor Plenum and Indoor/Outdoor cable with the additional benefit of the armor which makes it suitable for outdoor installations.

Outdoor Aerial with Messenger

This cable has a steel messenger for use spanning from building to building or pole to pole etc. Due to the fact that it contains a jell-filled cable, it is limited to a maximum of 50 feet running indoors.

>Fiber Type

The 62.5/125 µm (AKA: OM1) has been the most popular multimode fiber choice throughout the 80's, 90's and into the early 2000's and was the most common multimode fiber used and yet it has the lowest data carrying capacity and shortest distance limitations as compared with other Multimode fiber types. It is generally accepted that 62.5/125 Multimode will soon be obsolete for the purpose of new installations.

NOTE: If you currently have 62.5/125 µm fiber installed in your office, building or campus you need to continue to use 62.5/125 µm fiber patch cables to connect to it. Attempting to mate two different fiber core sizes can lead to high loss and is therefore strongly not recommended. We recommend at least OM2 or higher for new installations.

The 50/125 µm core size comes in three different classifications (OM2, OM3 and OM4). Below are the types of fiber available


OM1 will soon be rendered obsolete because in contrast 50/125 fibers have a much higher bandwidth capacity. Also consider the fact that OM2 is usually about the same price as OM1. The only practical use for OM1 cables would be for use in extending and existing OM1 cable run. OM1 typically has an orange jacket.


OM2 will become the cable of choice for those who have no intention of upgrading to 10 Gb. OM2 can run 1 Gb Ethernet for a maximum distance of 220 meters. OM2 typically has an orange jacket.

Category Fast Ethernet 100BASE-FX 1 Gb (1000 Mb) Ethernet 1000BASE-SX 10 Gb Ethernet 10GBASE-SR 40 Gb Ethernet 40GBASE-SR4 100 Gb Ethernet 100GBASE-SR10
OM1 (62.5/125) 2000 m 220 m 33m Not supported Not supported
OM2 (50/125) 550 m
(mode-conditioning patch cord required over 300m)
82m Not supported Not supported
OM3 (50/125) (Laser Optimized) 300m 100m (330m) 100m
OM4 (50/125) (Laser Optimized) 400m 150m (550m) 150m

* NOTE: Check with equipment manufacturers to verify the above distances and speeds.


OM3 will become the cable of choice for those who seek to run 10 Gb Ethernet either now or in the near future. OM3 will soon be the most popular Multimode choice especially for Data Centers. OM3 typically has an aqua color jacket.


OM4 will be the cable of choice for Data Centers due to its ability to run 100 Gb at greater distances. OM4 typically has an aqua color jacket.

>Frequently Asked Questions

Use OM1 only to extend existing fiber runs. Otherwise use a minimum of OM2.
OM1 is 62.5/125 and OM2 is 50/125. The 50/125 core of OM2 has a higher bandwidth capacity.