Information Technology Reference
In-Depth Information
The fundamental component for copper wiring termination in the TR is the punch-
down block. The punchdown block can take many forms, and has over the years
evolved into a rather complex “system” component. The punchdown can even be
incorporated into a patch panel, but we will talk about that later.
There are two main types of punchdown blocks in common use: the 110 block
and the older 66M block, both originated by AT&T. Both types are now offered by
a number of companies, and versions of these block terminations are incorporated
into many products, including outlet connectors and patch panels. These two
punchdown types dominate the installed and new markets, so we will cover them in
some detail. We will also cover a couple of proprietary punchdown systems that are
available from only one manufacturer or are not as widely used.
Type 110 Connecting Blocks
The most popular style of cable termination block for structured wiring from
Category 5e to Category 6/AC6 is the type 110 connecting block.
1
The 110-style
block is a relative newcomer, compared to the older 66 block, described in the next
section. Even so, it has been in use for over three decades. The 110 system is
designed for higher wiring density and a better separation of “input” and “output”
cables than the older system. The 110 system is also important because the 4-pair
connecting block component is used for the insulation-displacement termination in
many patch panel and outlet jack systems by various manufacturers.
The 110 system consists of two basic components, the
110 wiring block
and the
110C connecting block
. The 110 wiring block, shown in Fig. 7.1, is a molded plastic
mounting block with “horizontal index strips” that organize and secure 25 pairs (50
wires) each. Blocks are available that accommodate 100 and 300 pairs. The 100-pair
block has four horizontal index strips, and the 300-pair block has 12. The 110A wiring
block has a 3.25-in depth from the mounting plane and is used in normal applications.
The empty space below the block makes feeder cable routing easy. A 110D
block is available with a 1.4-in depth for low-profile special applications.
The 300-pair wiring block illustrates the potential wiring density of the 110
system. It accommodates all 300 pairs in a 10.75-in square footprint. A 110T dis-
connect block is also available that provides the ability to disconnect a circuit for
testing in either direction.
1
Category 7 termination is not done with punchdown blocks, but rather consists of a terminating con-
nector array, similar to the way that fiber cables are terminated. See Chapter 8 for more information.
