Vehicle Interface Port (Vip); W4, W5, And W7 Control Heads; Vip Output Connections; Dash-Mount Installations - Motorola ASTRO W3 Service Manual

3-12
3.4

Vehicle Interface Port (VIP)

The vehicle interface port (VIP) allows the control head to control outside circuits in the vehicle and
to receive inputs from outside the control head. This results in greater flexibility and ease of
installation when interfacing to other systems in the vehicle. There are up to three VIP outputs that
can be used for relay control. There are also up to three VIP inputs that can accept input from
switches, etc.
3.4.1

W4, W5, and W7 Control Heads

The VIP outputs are controlled by microcomputer U1 pins 26, 27, and 28. A high level causes the
associated transistors Q71-73 to conduct up to 300 mA of current to ground. Primarily, these
transistors control external relays. The relay coil is connected between the VIP output pin and
SWB+. See the installation manual for connection details.
The VIP input lines connect to U4, pins 22, 25, and 35. U4 acts as an inverting stage, passing the
VIP input signals to U1, pins 29-31, to be read by the microcomputer. VIP inputs normally connect to
ground via a normally open or normally closed switch.

3.4.1.1 VIP Output Connections

3.4.1.1.1 Dash-Mount Installations

Two VIP outputs are available in dash-mount installations. VIP OUT 1 is on pin 12 of the rear
accessory connector; VIP OUT 2 is on pin 3. These connections are used to control relays. Connect
one terminal of the relay coil to SWB+ (Rear Accessory Connector pin 4). Connect the other relay
coil terminal to one of the VIP outputs. See the installation manual for the horn and lights connection.
September 26, 2003
Table 3-6. Standard Jumper Configurations (Continued)
Jumper Number
JU5
JU7
JU8
JU9
JU10
JU11
JU12
JU13
JU16
JU17
JU18
JU19
JU20
JU21
JU22
Theory of Operation: Vehicle Interface Port (VIP)
Normally
IN
IN
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
IN
IN
IN
OUT
OUT
6881096C77-O