Information Technology Reference
In-Depth Information
routed vertically from the jack to the nearest cable raceway and tucked out of sight.
From two to four rows of patch jacks can be accommodated easily, representing 24
to 48 patch positions on an average panel. At the side rails, vertical raceways can
be provided to route the cords to patch or equipment positions on other levels of a
rack. Cable trays and ladders (open bottom trays with cross pieces between the side
runners) can be used to route the cords from rack to rack across the top of the racks.
Computer rooms with raised floor panels can route the cables beneath the floor, but
the above-rack method is much easier to maintain and can be made to look as neat.
Connectorized Patch Panels
A type of patch panel is available with pre-connectorized jack connections, rather than
terminations for individual cables. This type of patch is used extensively with the con-
nectorized punchdown blocks, as described earlier, and it may be useful for the multi-
port equipment connections of larger hubs. The connectorized patch panel has one or
more multicircuit connectors mounted at the rear of the panel. The modular jacks are
each connected to the appropriate pins on the connector. Six 4-pair, 8-pin modular
jacks can be connected to a single 50-pin “telco” connector (also called an Amphenol
connector), if all pins of the jack are connected. This means that you would have to use
four 50-pin connectors for a 24-position patch panel. Some patch panels connect only
two pairs to each jack position and support 12 jacks per 50-pin connector.
These panels are wired to support only one style of network connection, such
as 10/100BaseT (which uses pins 1, 2, 3, and 6) or Token-Ring (which uses pins 3,
4, 5, and 6). Obviously, the styles may not mix, so you may have to replace the panel
if you change your network hardware.
The mapping of connections from the connector to the jack is critical, as each
pair on the jack generally has a preassigned circuit function, such as Transmit +/-.
If used to provide connectivity to a multiport hub card, the connectorized patch
panel takes the place of the modular equipment jacks. In a conventional modular
jack hub, the hub connector pins are each assigned a specific network function, and
any 4-pair equipment cord wired straight-through will automatically put the proper
signals on the pins of the horizontal patch panel (and thus the cable).
If a connectorized patch panel (Fig. 8.5) is used, the signals are mapped from
a multicircuit connector to each modular jack on the panel. Instead of an equipment
cord from the hub to the horizontal patch, a patch cord is connected from each hub-
port jack on the connectorized patch to the corresponding station jack on the hori-
zontal patch.
If the mapping from the 50-pin connector to the jack is wrong, the signals will be
reversed or totally miswired and the connection will not work. The standard mapping
