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 pa
-
rameters 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 baud rates.
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 pro-
gram).
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 num
-
ber 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:
+
In multi-port devices, LTP is a multi-port command. This means that on
multi-port devices the LPT command can be used to configure port 1 and port 2
independently, each with their own digipeating path. The following example is
for the case of a single-port device; for dual port devices, see the command
refererence for the device.
GPS NMEA Interfacing Capability Packet Modes of Operation
KAM’98 v 8.3 183 User’s Guide
To Next Page
Loading...