I have an old 6500 with 6516a GBIC module (picture) and im planning to do some testing with it.
I've already looked over Cisco's product page, and im still having a hard time identifying what SFP plug will fit in this module, no idea what it even looks like.
Also, is it possible to connect an SFP+ LC (single mode) fiber to this 6516a module? or do i need to purchase some sort of converter?
This particular blade does not use SFP format transceivers at all. It uses GBIC format transceivers. You can find more information for this blade on the data sheet.
So, no, you won't be able to connect a SFP + LC connector with this hardware. There is no converter to allow you to insert a SFP into a GBIC slot. However, all you need is a different fiber cable to connect to a GBIC, they use SC connectors as opposed to LC.
GBICs and SFPs will communicate with each other just fine as long as they are the same type. So if you have an SFP on the other end of the cable, you would simply need a SC-LC fiber cable.
Since you mentioned single mode fiber, if the blade doesn't come with any GBICs (or the right kind), you would also most likely need a 1000BASE-LX/LH GBIC as well (most common SM fiber transceiver, however there are others). Fortunately, SFP has quickly overtaken GBIC as the standard form factor (main advantage being it's smaller size), so you can often find second hand GBIC transceivers at a very low cost.
