Garmin TracPak GPS 30/30 SL Manual page 28

PGRME 36
PGRMT 47
PGRMV 26
PGRMF 79
LCGLL 36
LCVTG 34
The factory set defaults will result in a once per second
transmission at the NMEA specification transmission rate
of 4800 baud.
4.2.2 Transmitted Time
The GPS 30/30 SL outputs UTC (Coordinated Universal
Time) date and time of day in the transmitted sentences.
Prior to the initial position fix, the date and time of day are
provided by the on-board clock. After the initial position fix,
the date and time of day are calculated using GPS satellite
information.
The GPS 30/30 SL uses information obtained from the
GPS satellites to add or delete UTC leap seconds and
correct the transmitted date and time of day. The transmitted
date and time of day for leap second correction follow the
guidelines in "National Institute of Standards and Technology
Special Publication 432 (Revised 1990)" (for sale by the
Superintendent of Documents, U.S. Government Printing
Office, Washington, D.C., 20402, U.S.A.).
When a positive leap second is required, the second is
inserted beginning at 23h 59m 60s of the last day of a month
and ending at 0h 0m 0s of the first day of the following
month. The minute containing the leap second is 61
seconds long. The GPS 30/30 SL would have transmitted
this information for the leap second added December 31,
1989 as follows:
Date
311289
311289
Time
235959
235960
23