Garmin GPS 35 LP Technical Specification page 37

The bottom section contains program messages. Upload and download status messages will appear
here as well as any program error messages.
Commands:
D - Download Almanac:
The GPS25 sensor will be sent a command to download almanac information. GPS25PM.EXE will
create the file ALMANAC.DAT and locate it the current working directory. If an ALMANAC.DAT exists in
the current directory it will be over-written.
U - Upload Almanac:
The ALMANAC.DAT file located in the current working directory will be read, converted to GPS25 sensor
binary format, and sent to the GPS25 sensor. This command will over-write any almanac information
already in the GPS25 sensor.
E - Download Ephemeris:
The GPS25 sensor will be sent a command to download ephemeris information. GPS25PM.EXE will
create the file EPHEMERS.DAT and locate it in the current working directory. If an EPHEMERIS.DAT
exists in the current directory it will be over-written.
P - Position and Time Upload:
The program will prompt the user for the local time offset from UTC time. This offset is then used to
determine UTC time from the PC's real time clock. The UTC time is then uploaded to the GPS25
sensor. If an error occurs in the upload process a 'COMM ERROR' will be enunciated on the screen.
After the UTC time has been uploaded the user is prompted for Latitude and Longitude for position
uploading. An integer Latitude and integer Longitude should be entered on the same line separated by a
space. If the board has not yet obtained a position fix it will restart its startup sequence based on the
new position and time information.
R - Record Data
The program will prompt the user for a data file name. GPS25XL.DAT is the default. Once the file name
is obtained all information displayed in the top two sections of the screen will be formatted and written to
the data file. The format of this data file is described in the File Formats section. If the R option is
selected again, the current file will be saved and closed and a new file will be opened. Data files will be
over-written if same names are used.
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