Information Technology Reference
In-Depth Information
A
Horizontal
cable
Common
equipment
Horizontal
cross-connect
B
Horizontal
cable
Common
equipment
Horizontal
cross-connect
FIGURE 8.1
Two alternatives to cable termination and interconnection in the wiring closet. (a) Traditional
punchdown and cross-connect. (b) Direct patch-panel termination. The asterisk (*) indicates
optional components; patch cord may be connected directly to the common equipment.
sisting of one to four twisted pairs) is punched down on the appropriate contacts of
a common-equipment connecting block, routed across the frame, and the other end
punched down on the contacts for the station cable (the horizontal cable). Changes
require you to rip out a punched-down cross-connect jumper and install a jumper
to the new location.
Connections in the punchdowns are theoretically gas-tight, so corrosion and
signal deterioration over the long term are rare. This method works fine for LAN
wiring, although you must pay attention to the issues of pair twist, minimum bend
radius, and other cable-care considerations when wiring LAN cross-connects, just
as you did with the installation of the station cable. This first method is pure cross-
connect wiring, without the use of any patch panels.
