| Demarcation point (demarc) |
When you contract with a local exchange carrier
(LEC) for data or telephone services, they
install a physical cable and a termination
jack onto your premises. The demarcation point (demarc) is the line that marks the boundary
between the telco equipment and the private
network or telephone system.
- Typically, the LEC is responsible for all
equipment on one side of the demarc, and
the customer is responsible for all equipment
on the other side of the demarc.
- The demarc is also called the minimum point
of entry (MPOE) or the end user point of
termination (EU-POT).
- The demarc is typically located in the bottom
floor of a building, just inside the building.
For residential service, the demarc is often
a small box on the outside of the house.
- For business installations, the demarc is
often identified by an orange plastic cover
on the wiring component.
|
| Main Distribution Frame (MDF) |
The main distribution frame (MDF) is the
main wiring point for a building. The MDF
is typically located on the bottom floor
or basement. The LEC typically installs the
demarc to the MDF. |
| Intermediate Distribution Frame (IDF) |
An intermediate distribution frame (IDF)
is a smaller wiring distribution point within
a building. IDFs are typically located on
each floor directly above the MDF, although
additional IDFs can be added on each floor
as necessary. |
| Demarc extension |
As it name implies, a demarc extension extends
the demarcation point from its original location
to another location within the building.
- The demarc extension typically consists of
a single wire bundle that attaches to the
existing demarc and supplies a termination
point to a different location.
- You might need a demarc extension if your
network occupies an upper floor of
a building.
The LEC will typically install the
demarc
into the MDF on the bottom floor,
and you
will need to install an extension
to place
the demarc into the IDF on your floor.
- You are typically responsible for installing
the demarc extension, or the LEC might do
it for an additional charge.
|
| Vertical cross connect |
A vertical cross connect connects the MDF
on the main floor to IDFs on upper floors.
Cabling runs vertically (up and down) between
the MDF and the IDFs. |
| Horizontal cross connect |
A horizontal cross connect connects IDFs
on the same floor. Cabling runs horizontally
(sideways) between the IDFs. |
| 25 pair |
25 pair cables consist of 25 pairs of copper
wires in a single bundle (containing
a total
of 50 wires). 25 pair cables are often
used
for telephone installations that have
multiple
telephone lines, to replace multiple
Cat3/5/5e/6
cables in a single bundle, and for
horizontal
and vertical cross connects between
the MDF
and IDFs. Individual wires within the
25
pair cable use the following color
coding
scheme:
- A total of 10 colors are used in two different
groups:
- Group 1 colors are white, red, black, yellow,
and violet.
- Group 2 colors are blue, orange, green, brown,
and slate.
- There are 5 wires of each color.
- Every colored wire in group 1 is paired with
each color in group 2. For example, you will
have the following pairs for the white wires:
- White with blue
- White with orange
- White with green
- White with brown
- White with slate
- Instead of using solid colors, some schemes
use striped wires to uniquely identify each
wire and its matching wire. For example,
the white wire with a blue stripe is twisted
with the blue wire with a white stripe, and
the red wire with the orange stripe is twisted
with the orange wire with the red stripe.
An RJ-21 connector is used to connect 25
pair cable to other wiring devices, or you
can manually connect each wire to the necessary
location. |
| 100 pair |
100 pair cable consists of 100 pairs of copper
wires in a single bundle (containing
200
wires).
- 100 pair wires use the same coloring scheme
as 25 pair wires, repeated 4 times.
- Each bundle of 25 wires is often wrapped
together with a colored nylon string to help
separate wires of the same color.
|
| 66 block |
A 66 block is a punchdown block used for
connecting individual copper wires together.
- The 66 block has 25 rows of four metal pins.
Pushing a wire into the pin pierces the plastic
sheath on the wire, making contact with the
metal pin.
- There are two different 66 block configurations:
- With the 25 pair block (also called a non-split
block), all 4 pins are bonded (electrically
connected). Use the 25 pair block to connect
a single wire with up to 3 other wires.
- With the 50 pair block (also called a split block), each set of 2 pins in a row are bonded.
The left pin is connected with the middle
left pin, while the right pin is connected
with the middle right pin. Use the 50 pair
block to connect a single wire to one other
wire.
- With a 50 pair block, use a bridge clip to
connect the left two pins with the right
two pins. Adding or removing the bridge clip
is an easy way to connect wires within the
row for easy testing purposes.
66 blocks are used primarily for telephone
applications. When used for data applications:
- Be sure to purchase 66 blocks rated for Cat5.
- When inserting wires in the block, place
both wires in a pair through the same slot
to preserve the twist as much as possible.
|
| 110 block |
A 110 block is a punchdown block used for
connecting individual wires together.
- The 110 block comes in various sizes for
connecting pairs of wires (for example 50,
100, or 300 pair).
- The 110 block has rows of plastic slots.
Each plastic slot connects two wires
together:
- Place the first wire in the plastic slot
on the 110 block.
- Insert a connecting block over the wire and
slot. The connecting block has
metal connectors
that pierce the plastic cable sheath.
- Place the second wire into the slot on the
connecting block.
- C-4 connectors connect four pairs of wires;
C-5 connectors connect five pairs of wires.
- When connecting data wires on a 110 block,
you typically connect wires in the following
order:
- White wire with a blue stripe, followed by
the solid blue wire.
- White wire with an orange stripe, followed
by the solid orange wire.
- White wire with a green stripe, followed
by the solid green wire.
- White wire with a brown stripe, followed
by the solid brown wire.
Tip: Use BLOG (BLue-Orange-Green) to remember
the wire order, and remember to start with
the white striped wire first.
110 blocks can be used for both telephone
and data, and are better suited for Cat5
installations. When using for Cat5 wiring,
be sure to preserve the twists in each wire
pair to within one-half of an inch of the
connecting block. |
| Patch panel |
A patch panel is a device that typically connects individual
stranded wires into female RJ-45 connectors.
For example, you might connect 4 pairs
of
wires from a punchdown block to a port
on
the patch panel. On the patch panel,
you
then connect drop cables (cables with
RJ-45
connectors) to the patch panel on one
end
and a computer on the other end. |