I'm fairly new to fiber cabling. I have an OM1 cable (running 750 metres) already installed on a site that currently works fine on an old system that is being upgraded. I'm trying to find out if these Cisco compatible SFP transceivers (http://www.farnell.com/datasheets/2037500.pdf) will be able to run at 10 and hopefully 100 Mbps. Fiber will be spliced for duplex LC connectors.
2950s being specified.
SFPs run at 1310nm which according to this table:
Is this better than running a SFP at 850nm. Greater performance/distance for OM1.
Can anyone provide me their thoughts on if it is compatible? I read that OM1 and 2 is LED and OM3 and OM4 is laser? I am slightly confused by this.
Best Answer
Not likely.
The transceiver you've linked to is for the 1000BASE-LX10 standard. It uses 1310 nm wavelength and has a reach of 550 m on 500 MHz·km fiber like your OM1. You'd exceed the reach by 30+% which is not likely to work (reliably). OM1 has limited use, the higher the bandwidth the shorter the reach. A PHY only runs at the indicated speed(s). There's no throttling when the link quality is poor, it simply won't work at all or cause errors.
Since you're only looking for 10 or 100 Mbit/s - the according PHY is 100BASE-FX which has a reach of 2000 m on MMF (pretty much any grade). Transceivers are still available, check for compatibility with your switches.
If you require more bandwidth you can try working around with link aggregation, WDM and such - but most often running higher-grade fiber is the better option in the long run (I'd go for single mode for this distance).
PHYs up to 100 MBit/s often use LED sources which are limited by frequency and are rather unfocused for fiber coupling. Gigabit+ PHYs require lasers that are very focused and benefit from OM3+ "laser-optimized" fiber. You can use any combination but the lower the fiber quality, the shorter the reach for higher speeds.