1.6 TELEPHONE LINE WIRING – MULTIPLE UNITS
If any alarm systems are installed on the phone line, be sure that the alarm interface precedes the
1812 by-pass switch interface.
DOORKING
1875-010
GND
C.O.
1 2
PH IN
3 4
PH OUT
5 6
HOME
7 8
ENTRY
BY-PASS
Ground
C.O.
Demarcation
Home
Telephones
Phone In - 1
Phone In - 2
Case Ground - 3
Phone Out - 4
Phone Out - 5
1812 #1
Main
Terminal
1 - Phone In
2 - Phone In
3 - Case Ground
4 - Phone Out
5 - Phone Out
1812 #2
Main
Terminal
Use only twisted pair telephone
wire that is rated for direct
underground burial. Do not use
wire designed for indoor
applications.
Use this wiring scheme if more than one 1812 will be installed on the same phone line. Up to five (5)
1812 units may be wired in series using this method. Additional units are connected PHONE OUT to
PHONE IN; PHONE OUT to PHONE IN, etc.
Each 1812 unit must be programmed for MULTIPLE SYSTEMS, each must be programmed with a
unique ATTENTION NUMBER, and each must be programmed with a unique MASTER CODE.
1. Connect PHONE IN wires from BY-PASS switch to 1812 #1 PHONE IN terminals 1 & 2.
2. Connect PHONE OUT wires from 1812 #1 (terminals 4 & 5) to 1812 #2 PHONE IN
terminals 1 & 2.
3. Connect PHONE OUT wires from 1812 #2 (terminals 4 & 5) to PHONE OUT terminals on
the BY-PASS switch.
4. Check for polarity on the phone "IN" wires, terminals 1 and 2. Terminal 2 must be positive
with respect to terminal 1. Set a VOM meter to measure DC volts. Place the positive lead
on terminal 2 and the negative lead on terminal 1. If the meter shows a positive voltage -
OK. If the meter shows a negative voltage (needle moves off scale to the left), reverse
the wires on terminals 1 and 2.
5. Surge protection is recommended on both phone in and phone out lines. Use DoorKing
phone line surge suppressers (p/n 1877-010) or equivalent.
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1812-065-M-3-07
