http://www.w4rp.com/ref/pinouts_for_rj45_jacks.htm
http://www.hotlinkdata.com/tech-corner/wiring-and-jacks.html
http://www.prsol.com/cpd.html
http://www.dasblinkenlichten.com/how-to-t1-circuits-and-wiring/
http://www.pulsewan.com/data101/pdfs/t1basics.pdf