DoorKing 1812 Access Plus - Manual (Page 14)

1812-162-M-1-12 12
Telephone
Wire Conduit
High Voltage
Power Wire
Conduit
Electrical field from power wires.
18” minimum
Underground Cutaway
Note: Do not run telephone wires and high voltage power
wires in the same conduit. Separate the high voltage
conduit and the telephone conduit by at least 18 inches to
prevent any electrical field interference that could occur.
“Tip” and “Ring” Definition.
Common terms in the telephone service industry referring to the two wires or sides of
an ordinary telephone line. Tip is the ground side (positive) and Ring is the battery (negative) side of a phone circuit. The
ground side is common with the central office of the telephone company (telco); the battery side carries -48 volts of DC voltage
when in an “Idle” or “On Hook” state.
Phone Line Polarity.
Tip and ring reversal is mostly immaterial, except for special circuits including DID (Direct Inward
Dialing) trunks, T-1 lines, and ground start lines where the field side (“terminal”) equipment (a company's PBX switch, for
example) can only function correctly with correct tip and ring polarity.
Wire Type.
It is extremely important to use the correct type of wire in telephone applications. Since the 1812 requires
phone lines to be run outdoors or in an underground environment, we recommend that you use only wire that is rated for
direct underground burial. For example, use Cat5e Gel Filled (flooded) UV Resistant Direct Burial Cable run in conduit for
your 1812 phone line requirements. Do not use thinly insulated brown-jacketed telephone wire (the type found in the walls of a
house) for outdoor or underground phone line wiring. Using improper wire can cause noise and hum on the phone line. Be
sure that phone wire pairs are twisted.
Wire Size and Distance.
Phone lines can be run up to 3600 feet, provided that the proper wire size is used.
1.3 Telephone Line Wire
Be sure to observe electrical safety when working with phone lines. Phone lines carry electricity and the ring voltage can deliver
a substantial jolt. The best policy is to disconnect the house phone from the phone company Network Interface Device (also
known as ‘Demarcation Device’) before working on the wiring.
In most residential homes, the phone cable contains four wires; green, red, black, yellow. The green and red are twisted to make
one pair and the black and yellow are twisted to make another pair (This allowed for the addition of a second phone line since
telephones use only two wires). Most phone lines installed in the U.S. in the second half of the 20th Century have this type of
wire. This type of wire is now obsolete. All new telephone projects are using Cat5 wire. If you have Cat5 wiring in your home,
the conversion is simple:
The convention for Cat5 wire is as follows:
• Colored pairs match; e.g., WHITE/blue mark (Tip +) wire goes
with BLUE/white mark (Ring -) wire for one phone line, etc.
• The pairs are used in the order pictured: for the first line, you
use BLUE, for the second line you use ORANGE, etc.
• An easy way to remember this is that the colors run from the
sky to the earth. BLUE sky comes first; ORANGE sunset second;
GREEN grass third; BROWN earth last.
Cat5 Wire
Four Conductor
Wire
Tip (+)
1st Line
Wire
Conversion
2nd Line
3rd Line
4th Line
Green
Red
Black
Yellow
Blue Pair
Orange Pair
Green Pair
Brown Pair
Ring (-)
(+) Tip
(-) Ring
(+) Tip
(-) Ring
(+) Tip
(-) Ring
Older Residential
Homes
Modern Residential
Homes
Wire Size Max Distance
24 AWG
22 AWG
20 AWG
18 AWG
800 ft
1600 ft
2200 ft
3600 ft
Telephone Wire Run Table