OM1 (Optical Multimode 1) fiber optic cabling is considered an older and less capable multimode fiber type compared to more recent generations. While it may not be entirely obsolete, its use is limited, especially in comparison to newer multimode fiber types such as OM3 and OM4. OM1 has several characteristics that make it less suitable for modern high-speed networking applications:

1. Lower Bandwidth: OM1 has a lower bandwidth compared to newer multimode fibers. This limits its ability to support higher data rates over longer distances.

2. Short Reach: OM1 is suitable for relatively short-distance applications, typically up to 33 meters for Gigabit Ethernet (1GbE) and even shorter distances for higher data rates.

3. Large Core Diameter: OM1 has a larger core diameter (62.5 micrometers) compared to later multimode fibers like OM3 and OM4 (50 micrometers). The larger core diameter contributes to higher modal dispersion, limiting the achievable data rates and reach.

4. Legacy Applications: While OM1 may still be found in some existing installations, it is not recommended for new deployments, especially in applications requiring higher data rates such as 10 Gigabit Ethernet (10GbE) and beyond.

For modern networking applications, it is generally recommended to use higher-grade multimode fibers, such as OM3 or OM4, which offer improved bandwidth, lower modal dispersion, and better performance at higher data rates. OM1 may still be encountered in certain legacy systems or installations, but its use is diminishing as networks evolve to higher speeds and longer distances.

When planning a new fiber optic installation, it is advisable to consider the specific requirements of the network and select the appropriate multimode fiber type based on factors such as data rate, reach, and future scalability.