Handbook for Sound Engineers

1500 Chapter 39

AMP makes quality modular connectors, but the
secondary crimp point is located in a different position
from everyone else’s connectors. Fig. 39-41 shows a
standard crimp die and an AMP plug. Point “A” is the
primary crimp point, and should fold the primary strain
relief tab in the plug down so that it locks against the
cable jacket. At the opposite end of the plug, the contacts
are pressed down into the individual conductors. The
“B” secondary crimp point secures the individual
conductors so that they do not pull out of the contacts.
AMP puts this crimp in a different location from all
other manufacturers. If AMP connectors are used in a
standard crimper they will either jam, bend, or break the
crimp die. If standard connectors are used in an AMP
crimper, the die will usually break. Once either type of
plug is properly crimped onto the wire, they are inter-
changeable and will work properly in any mating jack,
Fig. 39-41.

Some plugs are made with inserts that guide the
wires. These can make the job of properly assembling
the connector easier. Some connectors made with inserts
may also provide better performance than Cat5, Figs.
39-42 and 39-43.

39.11.15.1 Pairing, Color Codes, and, Terminations

Cat5 cable consists of four twisted pairs of wires. To
minimize the crosstalk between the pairs, each pair is

twisted at a slightly different rate. For fast Ethernet, one

pair is used to transmit (pins 1 and 2) and another pair is

used to receive (pins 3 and 6). The remaining two pairs

are terminated but unused by fast Ethernet. Although

only two of the four twisted pairs are used for fast

Ethernet, it is important that all pairs be terminated, and

that the proper wires be twisted together. Standards set

forth by EIA/TIA 568A/568B and AT&T 258A define

the acceptable wiring and color-coding schemes for

Cat5 cables. These are different from the USOC wiring

Standards used in telecommunications, Figs. 39-44 and

39-45.

Note that there are two conflicting color code stan-

dards for data use of the RJ-45 connector. Both work

just fine, but to avoid problems make sure that one of

the standards is selected and used uniformly throughout

a facility.

Figure 39-41. A standard crimp die above an AMP
connector. Note the misalignment of the secondary strain
relief crimp point B. An AMP connector will jam in a stan-
dard crimper, while a standard RJ-45 will usually break an
AMP crimp die.

B

A

Figure 39-42. An RJ-45 connector that uses an insert to

guide the individual conductors into the connector. Such a

connector can be easier to properly assemble on a cable.

Some connectors made this way provide performance well

beyond Cat5.

Figure 39-43. RJ-45 pin numbering.

Pin 1