Horn-Ring Transfer Relay - Motorola MCS 2000 Installation Manual

6-4
6.2

Horn-Ring Transfer Relay

In order to make Siren operation more convenient under emergency conditions, the vehicle's Horn-
Ring (or buttons) can be used to control siren functions (refer to
convenience allows the driver to concentrate on the road and traffic conditions.
Figure 6-4 shows wiring diagrams for connecting the Horn-Ring via a transfer relay for both negative
and positive ground systems. As an alternative, a simple momentary contact pushbutton (normally
open) may be installed in the vehicle, in a location convenient to the driver.
Horn
Ring
To Control Head VIP
Output Programmed for
Horn-Ring Transfer
To SW B+ at
VIP Connector
Any SPDT Relay with 12V Coil
and Suitable Contact Ratings for
Vehicle Installation
To Control Head VIP
Input Programmed
for Horn-Ring
Negative-Contact Horn-Ring
6.3 Disassembly and Assembly
Item numbers in parentheses refer to parts identified in
manual.
6.3.1 Disassembly
1. Place the Siren/PA on a workbench with the top cover (2) upward. Loosen four screws (1)
and remove the top cover (2) from the chassis (8).
2. Remove the component side shield cover (27) by prying the corners from the shield fence
(28) and lifting upward.
3. Remove the main PC board as follows:
a. Remove the screw (29) near the connector (11).
b. Remove the screw (12) and bracket (13) that attach the bus assembly (14).
c. Remove two screws (15) from either side of the PC board (16).
December 2, 2003
Installation, Disassembly, and Assembly: Horn-Ring Transfer Relay
Under Hood
Horn Relay
Break
Here
+ 12V
N.C.
COM.
N.O.
To Control Head VIP
Output Programmed for
Horn-Ring Transfer
To Control Head VIP
Normally-Open
Momentary
Contact Pushbutton
Figure 6-4: Siren/PA Horn-Ring Connections
Chapter 2 on page
Horn
Horn
Ring
+ 12V
To SW B+ at
VIP Connector
Input Programmed
for Horn-Ring
Positive-Contact Horn-Ring
To VIP Input Programmed for Horn-Ring
To DIG. GND at VIP Connector
Pushbutton Connections
Figure 8-6, on page 8-9
2-2). This
Break
Here
To Horn
N.C.
COM.
N.O.
To DIG. GND at
VIP Connector
NOTE: Locate Pushbutton
in a Location Convenient to
the Driver
MAEPF-26792-O
in Chapter 8
6881096C46-O
of this