Work Area Cabling
Faceplates and Jacks are the connectors that terminate the cabling inside the walls to the outside. Faceplates come in many different colors and sides. Most faceplates fit right over a standard size electrical box. Jacks simply connect to the cable inside the wall via special clips and have a connector for a computer or other network device.
Some people simply try to crimp on RJ-45 connectors. Even though it might work, it is not a good idea because you could easily break the cable, causing trouble later on. Faceplates and Jacks are your insurance policy. Would you run an electrical outlet and then just simply leave the wire hanging out of the wall? It is like the same thing. It looks bad and could cause problems.
(Table Courtesy of the Siemon Company)