User Guide

16
SECTION 4
SOFTWARE INTERFACE
This section describes the details of the serial port
commands through which the HI-204
III is controlled and
monitored. The serial port commands allow users to set the
receiver parameters, configure output message type, and
retrieve status information. The baud rate and protocol of
the host COM port must match the baud rate and protocol
of the GPS receiver serial port for commands and data to
be successfully transmitted and received. The default
receiver protocol is 4800 bps, 8 data bits, 1 stop bit, and
none parity.
4.1 NMEA OUTPUT MESSAGE SPECIFICATION
The HI-204 III supports NMEA-0183 output format as
defined by the National Marine Electronics Association
(http://www.nmea.org). The currently supported NMEA
messages for GPS applications are:
GGA
GLL
GSA
GSV
RMC
VTG
Global Positioning System Fix Data
Geographic Position Latitude / Longitude
GNSS DOP and Active Satellites
GNSS Satellites in View
Recommended Minimum Specific GNSS Data
Course Over Ground and Ground Speed
APPENDIX B
DEFAULT VALUES
The product has the following factory preset default values:
Datum:000 (WGS-84)
NMEA Enable Switch:GGA ON
GLL ON
GSA ON
GSV ON
RMC ON
VTG ON
Checksum ON
Baud Rate:4800 Baud
Elevation Mask:5 degrees
DOP Mask:DOP Select: Auto
GDOP: 20
PDOP: 15
HDOP: 8
Receiver Operating Mode:Normal Mode (without 1PPS)
Commands can be issued to the HI-204L to change the settings of the
receiver. The new settings will remain effective on next power-on as
long as the on-board rechargeable backup battery is not discharged.
After the backup battery is discharged, factory preset default settings
will be used.