1.4 Telephone Line Wiring 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 (see chart).
The convention for Cat5 wire is as follows:
• Colored pairs match; e.g., WHITE with blue
mark goes with BLUE with white mark for one
phone line, etc.
Old Wiring
Four Conductor
Modern Wiring
Cat5e or Cat6
Tip 1 = WHITE / Blue Mark
Ring 1 = BLUE / White Mark
Tip 2 = WHITE / Orange Mark
Ring 2 = ORANGE / White Mark
Tip 3 = WHITE / Green Mark
Ring 3 = GREEN / White Mark
Tip 4 = WHITE / Brown Mark
Ring 4 = BROWN / White Mark
Red
Black
Yellow
Green
• 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.
"Tip" and "Ring" are 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.
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.
Phone lines can be run up to 3600 feet, provided that the proper wire size is used. Refer to the chart
at the top of the next page.
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