Information Technology Reference
In-Depth Information
color codes to match the wire colors. Pin numbers may also be printed on the hous-
ing to help the installer.
Nonmodular Jacks for Category 7
For some time, it has been realized and documented that the old-reliable RJ-45 style
of 8-pin modular plug and jack and the crossed-over wiring pattern are the biggest
single contributors to the limitation of copper link performance. “Old-reliable”
causes crosstalk, return loss problems, shielding issues, EMI, and is generally a pain
to assemble. Data networking, and with it structured cabling, have moved into the
radio-frequency (RF) domain, and the modular plug is a terrible RF connector.
With the advent of Category 7 performance standards, ranging from 600 to
1200 MHz, the old RJ-45 just won't do the job any longer. Frankly, it is a connec-
tor whose time is up. New nonmodular connectors (for lack of a better name) have
been developed that are much better to maintain impedance matching and shielding
in a very high speed data link. These connectors support the new Cat 7 cables, with
individually screened balanced pairs, and avoid all of the sins of the RJ-45, while
maintaining a similar profile for snap-in jacks and snap-lock connections. An exam-
ple of a high-performance Category 7 nonmodular connector is shown in Fig. 6.12.
The standard pin connections for a variety of modular jack styles are shown in Fig.
6.13. Modular jacks are used for many different purposes, of which LAN wiring is
only one.
FIGURE 6.12
A nonmodular Category 7 jack. (Courtesy The Siemon Company.)
