Garmin TracPak GPS 30/30 SL Manual page 24

<4> Longitude hemisphere, E or W
<5> Current UTC date, ddmmyy format
<6> Current UTC time, hhmmss format
<7> GPS 30 - Not used
GPS 30 SL - Acquisition command, R - Restart, A-
Start Autolocate.
approximately 7 minutes after the board is powered
up and has failed to obtain a fix. Autolocate can be
started immediately on receipt of this command.
This command is helpful if initial time and/or position
is known to be significantly inaccurate. The Restart
command is not needed during normal operation.
4.1.3 Configuration Information ($PGRMC GARMIN
proprietary format)
The $PGRMC sentence provides information used to
configure the GPS 30/30 SL operation. This information
will default to automatic fix mode, World Geodetic System
1984 (WGS-84) earth datum and automatic differential
mode when more than 15 minutes have elapsed without
power in the GPS 30. The GPS 30 SL will store this
information in non-volatile memory and will be used for all
subsequent power cycles. This sentence is echoed by the
GPS 30. The GPS 30 SL will echo the sentence if the data
is accepted. If the data is unreasonable then the $PGRMC
sentence is sent containing current values used in each of
the fields. Receipt of $PGRMCE will also cause the board
to sent $PGRMC will current values.
$PGRMC,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9><10>,<11>,
<12>*hh<CR><LF>
<1> Fix mode, A=automatic, 2=2D exclusively (host
system must supply altitude), 3=3D exclusively
<2> Altitude above/below mean sea level, -1500.0 to
18000.0 meters
<3> Earth datum index. If the user datum index (96) is
specified, fields <4> through <8> must contain
valid values. Otherwise, fields <4> through <8>
Normally autolocate begins
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