In general, PCs, printers and so forth rely on DHCP (Dynamic Host Control Protocol) to obtain an IP address (which identifies it on the network). Your router is (usually) the DHCP server (which hands out IP addresses on demand). If you use a CAT5e cable to connect a printer directly to a printer, you will need to allocate static IP addresses (in the same subnet) to both machines. If your PC is set to DHCP, and no DHCP server can be found, then Windows will allocate an IP address in the 169.254.x.x What your printer will do is dependent on the printer's firmware. You are getting into the realms of advanced TCP/IP networking, so reading up on this is probably the best idea.