Digital Key Switch  (490-0535A)      Connections       Faxback Doc. # 6863

The Digital Key Switch is compatible with many alarm systems.  However,
some alarm systems might not use all of the Digital Key Switch's
connections and features, and each system will require some variations in
wiring connections.  If you are using a Radio Shack alarm system, see the
separate wiring diagrams for exact connections.

REMOTE Normally Open/
Normally Closed Terminals - Connect the appropriate pair of the terminals
                            (N.O. or N.C.) to the remote arm/disarm
                            terminals on your alarm; consult the manual
                            for your system.  The center terminal is a
                            common connection for both N.O. and N.C.
                            arm/disarm switches.

Note:  Systems might vary as to whether the armed or disarmed state of
       their arm/disarm switch is considered to be the "normal" state.

      LATCH IN/OUT Switch - Set this switch for the type of switch closure
                            necessary to operate your system's arm/disarm
                            switch (latching=IN, momentary=OUT).  If you
                            are not sure what type of closure is needed,
                            check your system's owner's manual or contact
                            the manufacturer.

Be sure the LATCH IN/OUT switch is set to the OUT position when using the
49-450 or the 49-470 alarm panel.

NOTE:  You must set the LATCH IN/OUT switch before you connect power to
       the DIGITAL Key Switch.  If you try to set the switch after power
       is applied , the microprocessor might not recognize the setting.

TAMPER/PANIC (N.O.) Terminals- Connect these terminals to the normally
                               open tamper/panic/24-hour loop on your
                               alarm system.  If your system only has a
                               normally closed panic loop, these terminals
                               cannot be used.

IMPORTANT!  'Normally closed' and 'Normally open' are terms related to
types of sensors used in your alarm systems.

      ARM LED Terminals (+/-)- Connect to the remote arm indicator
                               terminals on your alarm system.  Be sure to
                               observe the marked polarity (+ and -).

Note:  Some systems might not have connections for remote arm indicators.

If your system has the schematic symbol for a diode above its terminals
instead of polarity marking, use the following drawing to determine the
correct connections.

    LOOP LED Terminals - Connect to the remote loop indicator terminals on
                         your alarm system.  Be sure to use the marked
                         polarity (= and -).

Note:  Some systems might not have connections for remote loop indicators.

If you system has the schematic symbol for a diode, instead of polarity
marking, use the previous illustration of the diode symbol to determine
the correct connections.

POWER Terminals (DC 10-20V) - Connect to a constant source of 10-20 volt
                              DC power provided by your alarm system.

Be sure to observe the marked polarity (+ and -).

    Jumper (on + terminals) - Allows for one connection to the "common"
                              side of the alarm circuit.  If your system
                              uses a negative (-) common, move the jumper
                              to the negative ARM, LOOP, and POWER
                              terminals.

If you cannot determine which terminal is "common" on your system, remove
the jumper and make separate connections for each terminal.

HOW AND WHEN TO USE THE JUMPER

The Digital Key Switch is supplied with a three-terminal jumper connected
to the positive (+) side of the ARM, LOOP, and POWER terminals.  This
eliminates multiple connections to the "common" indicator terminals.

If you system has common positive (+) connections for its indicators,
leave the jumper as it is and make connections similar to the drawing
below.

Alarm System with Positive (+) Common Circuits

If your system has a common negative (-) connections for its indicators,
move the jumper to the negative ARM, LOOP, and POWER terminals and make
connections similar to the drawing below.

Alarm System with Negative (-) Common Circuits.

If you system does not have polarity markings or other means of
determining the common terminal, contact the manufacturer or authorized
dealer for advice.

(LB/all-7/12/94)