for 10base-t/100base-tx connections, a twisted-pair cable must have two pairs of wires. each wire pair is identified by two different colors. for example, one wire might be red and the other red with white stripes. also, an rj-45 connector must be attached to both ends of the cable.
each wire pair must be attached to the rj-45 connector in a specific orientation.
the figure below illustrates how the pins on the rj-45 connector are numbered. be sure to hold the connectors in the same orientation when attaching the wires to the pins.
with 10base-t/100base-tx cable, pins 1 and 2 are used for transmitting data, and pins 3 and 6 for receiving data. the “+” and “-” signs in the tables below are used to represent the polarity of the wires that make up each wire pair.
