Here is a page that explains differential driving without appearing more complex than it really is:
Typically the datasheets make these things look intimidating, but they aren't really. The most important thing is to match your impedence on either side. A cat5 cable is designed for 100ohm impedence. On the differential transmission side, you split this as 50 ohm for each line. At the receive side, you place a 100 ohm resistor across the pair. You drive one twisted pair for each differential signal. D is the data you want to send, and R is the data you want to receive.