Twisted pair cables, CAT5, CAT5e, CAT6, CAT6+ (CAT7)

All the information you need on CAT5 (and up) cabling, very interesting if you are looking to wire up the office or your home.
Read more here:
http://www.epanorama.net/documents/wiring/twistedpair.html

Telecommunication and Data Communication Wiring Page:
http://www.epanorama.net/links/wire_telecom.html

Edited for update.