T1 Test Cable:

1->4
2->5
4->1
5->2

CAT5:
(It helps me to peg down all eight)

Pin, RJ45 Connector, RJ45 Connector

1, Green/White, Blue
2, Green, Blue/White
3, Orange/White, Orange/White
4, Blue, Green/White
5, Blue/White, Green
6, Orange, Orange
7, Brown/White, Brown/White
8, Brown, Brown

Additional Resources: