ACR Electronics ENGLISH Product Support Manual page 18

GPS interface cable using the wiring diagram information supplied by ACR and the GPS
unit manufacturer. Turn on your GPS unit and allow it to acquire the necessary satellites.
Make sure the output is set to NMEA 0183 with the GGA sentence configured if necessary.
Connect the NMEA 0183 interface cable to the GPS unit and the ACR beacon. The ACR
beacon "wakes up" every few seconds. As soon as it detects the presence of a valid data
source it will initiate a data down load.
Q. How long does it take to down load position coordinates from my GPS to my beacon?
A. Upon connection with a properly operating and fully acquired GPS unit, the ACR beacon
will take less than four minutes to synchronize and download coordinates. Subsequent
coordinate updates occur every 20 minutes. These subsequent position updates will take
from a few seconds to no more than 20 seconds to complete. If the interface cable is
disconnected you may need to wait for up to four minutes for the GPS and the beacon data
interchange to synchronize again.
Q. How does the GPS data get from my GPS to the beacon?
A. The GPS unit transmits data as electrical energy through the GPS interface cable to the
ACR optical interfacing connector. The ACR optical interfacing connector has an infrared
LED and sensor located in it. The electrical energy supplied by the GPS unit is converted
to infrared light in the ACR optical interfacing plug.
transmitted via infrared light to the beacon through the translucent beacon top cap or lens
when the ACR optical interface plug is properly engaged. The beacon has an infrared
detector that decodes the light pulses. ACR uses an optical interface design to eliminate
the potential for leaks and corrosion common to mechanically interfacing devices.
Q. How can I test my beacon to see if it has acquired GPS data?
A. Lift the switch to the test position, making sure not to break the tab.
acquired GPS data there will be a beep and LED flash within 4 seconds after the self-test
has completed.
Q. Does my GPS unit have to be set up in a special way to transmit position coordinates
via the NMEA 0183 interface?
A. For the GPS to transmit data make sure the NMEA 0183 output is turned on and the GGA
NMEA sentence is selected or turned on. Consult your GPS user's manual for information
on configuring the NMEA output.
Q. Does my beacon need any special set up to accept GPS data?
A. You do not have to do anything special to the beacon. If it is hooked to a valid data
source, that has been properly set up to deliver NMEA format with the GGA sentence, it
will automatically attempt to download the data and form an emergency message that
includes the position data.
Q. What is the maximum length my GPS cable can be?
15
Data from the GPS unit is
If the beacon has
Y1-03-0169 Rev. B