User's Manual

Sleep mode
This command puts the Tracker into a low-power sleep mode.
$SL [S=<seconds>|U=<[YYYY-MM-DD ]hh:mm:ss>]*xx
Parameter
Description
S=<seconds>
Sleep for this many seconds
U=<[YYYY-MM-DD ]hh:mm:ss>
Sleep until date (optional) and time
Returns one of:
Value
Description
$SL OK*xx
Sleep period accepted, Tracker is now
non-responsive
$SL WAKE,TIME*xx
Tracker has woken from selected sleep mode
$SL CLOCKNOTSET*xx
Clock not yet set from GPS
$SL ERR*xx
Invalid number of seconds or date/time value
$SL NOCOMMAND*xx
No S or U parameter is present
$SL ERR,NOTIME*xx
Attempt to sleep before time is set
The S parameter is the number of seconds to sleep. This value may range from 5 to 31536000
(approximately 1 year) seconds. A value not within this range will return $SL ERR. If the 
command is accepted, the Tracker will emit $SL OK and enter sleep mode for the requested 
duration.
The U parameter is a time and optional date the Tracker should sleep until and then wake. If the
date is not specified and the time to sleep until is less than the current time, the time is
presumed to be in the next day. For example, if the current time is 11:00:00 and $SL 
U=09:00:00 is issued, the Tracker will wake 22 hours from now. If a date and time are
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