When building or maintaining a fiber optic network, you will constantly face hardware decisions. Those decisions require constant research and relearning to stay up to date with modern choices, and that effort extends to cable options as much as switches or any other device in the network.
OM3 is a common type of multimode fiber. It utilizes a 50-micrometer core size and is capable of multi-gigabit data transmission across a range of distances. One of the most notable features of OM3 is the standardized aqua-colored jacket that makes it easy to identify.
Another key feature is that OM3 is optimized for laser equipment, allowing it to achieve high speeds.
OM3 is most commonly used for 10G connections because it can support them for up to 300 meters. That said, OM3 is capable of providing 40G and 100G connections — at ranges of up to 100 meters.
OM4 is considered an upgrade to OM3, but there are some important characteristics to cover. The first is that OM4 is completely reverse-compatible with OM3, meaning you can use OM4 cables with systems that currently run on OM3.
OM4 is another multimode fiber option, and in most cases, it also uses an aqua jacket (some companies use a purple jacket to distinguish it from OM3). This is another fiber cable with a 50-micrometer core, and it has the same speed ranges: 10G, 40G, and 100G.
One major difference (which will be covered in more detail later) is that OM4 supports longer cable runs than OM3 at each speed range. As a result, OM4 is more popular for connections above 10G (although it is also used for 10G runs in many applications).
Major Similarities Between the Two
What makes OM3 and OM4 so similar and easily confused? Two features top the list. Both cable types have the same jacket color (with the exception mentioned before). This makes it difficult to identify the cables when seeing a network for the first time.
Additionally, the fact that OM4 is reverse compatible means that you can find networks that use the two somewhat interchangeably, exacerbating confusion.
There’s also the fact that the two cable types operate with the same core size and in the exact same speed ranges.
In general, these are cables that perform many of the same functions in the same types of networks, and even at similar costs.
The Primary Differences Between OM3 and OM4 Fiber
All of that said, when you’re distinguishing between OM3 and OM4, there are a few keys that are worth noting.
First is bandwidth. OM4 has more than double the bandwidth of OM3 (check the table below for specifics). And, even though the two cables achieve the same data transmission speeds, OM4 can do it at considerably longer distances. At 10G speeds, OM4 can get up to 550 meters, and at higher speeds, it operates fine up to 150 meters.
This is why OM3 is commonly used for 10G applications (its 300-meter range is often sufficient) but OM4 is more popular for higher speeds (where 100 meters might not be enough cable length).
We can also compare prices. The exact price of a cable run will depend on the specifics of the network, but OM4 is often only $0.20 or less more expensive per meter of cable.
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