Kantronics KPC–3 Plus User Manual page 94

In addition to transmitting the beacons periodically, your TNC can store the transmitted
beacons in a location buffer (LTRACK) for later review. The size of the LTRACK buffer
is set by a command from the keyboard.
Setting Parameters in the TNC
To add GPS capability to your portable packet station, enter the required GPS
parameters into your TNC (from your PC), set ABAUD to 4800, and then cable your
TNC to the NMEA data port of your GPS unit.
Note. Most GPS units have a fixed NMEA data port rate of 4800 baud; however, some
advanced units allow other bauds.
To set up your TNC for GPS operation, you must first be communicating with it via your
terminal in the normal mode (Command Mode or with a Host Mode program).
First, set the GPSHEAD command to capture specific sentences from the GPS unit.
You can set up to four strings to be stored (one each) in the LT buffers. The command
would be GPSHEAD n string where n is the LT buffer number, and string is the name
of the GPS string to be stored.
For instance, if you want the TNC to store the $GPGGA string in LT buffer number 1,
use the command:
GPSHEAD 1 $GPGGA
In order to beacon an LT buffer, you must set the LTP and the BLT commands for that
LT buffer. Full details of the LTP and BLT commands can be found in the commands
section, but here's an example of how they could be used:
If you want LT 1 to beacon with a path of GPS via a digipeater (called DIGI), and you
want the beacon to occur every 30 minutes, use the following commands:
LTP 1 GPS via DIGI
BLT 1 EVERY 00:30:00
Several amateur groups, such as APRS (see the bibliography at the end of the GPS
section), have developed special programs for enhancing amateur GPS activities.
Check with them for current practice in setting GPS beacon paths, beacon rates,
and frequencies used in your area.
You can also set up a ―tracking buffer‖ to store the most recently transmitted LT
information for later retrieval. The size of the buffer and which LT buffers to store is
controlled by the LTRACK command. For instance, the command
LTRACK 5 LT1 LT2
would set the size of the LTRACK buffer to approximately 5 kbytes and store the LT 1
and LT 2 buffers whenever they are transmitted (as set by the BLT command).
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