Psion VH10, Руководство пользователя

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Chapter 5: Accessories
Wiring Vehicle Power to the VH10
133
Psion VH10 Vehicle-Mount Computer User Manual
Figure 5.25 Connecting the Switch or Relay to the DB9 Cable
Screen Blanking is implemented by using a DB9 port to monitor the electrical relay closure. When enabled,
the CTS/RTS pins of the DB9 port are continuously monitored by the screen-blanking application. To see
the pin configuration, see Figure 5.26 below.
When the vehicle is in motion, the switch/relay will close the circuit, allowing data packets to be sent or re-
ceived through the RTS and CTS pins. The computer knows the circuit is closed and will turn off the screen.
When the vehicle is not in motion, the switch/relay will open the circuit, preventing data packets from being
sent or received. The computer knows the circuit is open and will turn on the screen.
Figure 5.26 Screen Blanking DB9 Pin Configuration
VH10 power cable
DB9 cable
Lines to screen-blanking sensor (optional)
Lines to ignition switch (optional)
Note: Only CTS and RTS signals are used.
User-supplied switch/relay
that will provide an electrical
conductive connection when
the vehicle is in motion