For any device that connects to Ethernet, whether it be your computer, modem or wireless router, or even your DVR or cable box, you may be familiar with the slots on the back side, but chances are you do not know much about them, aside from the shape, and which cord inserts into them. Of course, there's the basic power cord, which plugs into the wall outlet, and in some instances, that cord is permanently connected to the device, and then there are most assuredly USB ports, which are found on most electronics now-a-days, being very common for many adapters currently.
Giving everything from access on your computer, to the updated listings for your guide on your DVR, the input that might be the most crucial is that of the Ethernet cable, which looks like a phone line and is what carries your internet signal. The spots in which you insert Ethernet cords are actually named SFP modules, which stands for Small Form-Factor Pluggable, and is a compact hot pluggable transceiver, which is utilized to administer the incoming Ethernet signal and makes the data viewable on your device.
For such a tiny piece, it does quite a lot of work, and if something ever happens to go awry and you lose the power to receive a connection to the internet, it might be related to this transceiver, but if you were to take your device in to get repaired, something to minuscule can end up costing you quite a bit, and you wouldn't even know how much you are getting overcharged. Cisco SFP modules are available in a range of price points for all levels of performance, and the part is actually very easy to replace, but if you go on the internet or to your local electronics store, you might probably find the part and replace it on your own for very little cash or effort on your part, and you'll be shocked how simple it is to really complete in the end.