Specifications

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5.3 Patch Cables
Patch cables connect computer to wall jack, and the patch panel to a hub or switch. Patch cables are
available in different length and colors. The T569A or T568B pin out option can be ignored since the
vendor terminates both ends, the choice of pair color does not matter.
Patch cables come in two versions, straight through and cross over. Straight through cables are used in
almost all circumstances. UTP Ethernet uses a point-to-point wiring scheme. The transmit port of the
computer connects to the receive port of the hub, and vice versa. If this default arrangement cannot be used,
for example connecting two computers directly together you need to use a cross over cable. Crossover
cable swaps transmit and receive pair at one end so like devices can be directly connected.
5.4 TIA 568A and 568B Pin out
A cause of much confusion when implementing structured wiring is the fact that two different connector
pin outs were defined T568A and T568B. They are nearly identical except pairs 2 and 3 are swapped.
Electrically this is of no consequence as long as both ends use the same pin out. TIA 570 Residential wiring
standard requires use of the T568A pin out.
Figure 10 UTP alternate pin outs
5.5 Uniform Service Ordering Code (USOC) Pin out
The RJ11 and RJ14 connectors are the two most common jacks used for residential phone systems. RJ11
(Registered Jack 11) is a 6 position modular connector terminating a single pair. RJ14 is also a 6-position
connector but it terminates two pairs, allowing a single jack to support two phone lines. RJ14 is by far the
most common configuration in new construction
Figure 9 Straight-through Patch Cable
Figure 8 Cross-over Patch Cable