Hemisphere GPS MBX-4, User Manual

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MBX-4 User Guide
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NMEA Message Elements
All NMEA 0183 messages possess a common structure, including a
message header, data fields, and a terminating carriage return and line
feed.
Example:$GPYYY,xxx,xxx,xxx…<CR><LF>
Null fields occur when no information is available for a field.
To issue NMEA commands, use a program with a terminal utility
running on a PC computer. You may type these commands into the
terminal window once you have matched the communication
parameters between the terminal program and the receiver. You must
ensure that when you press the Enter key on your PC to send a
command, it represents both a carriage return <CR> and line feed <LF>.
If a NMEA command is not working, this terminal facility option may
not be set correctly. Please contact your dealer, or Hemisphere GPS
Technical Service for more information.
Hemisphere GPS’ DGPS Command Center
If you are using Hemisphere GPS’ DGPS Command Center program, the
terminal window allows you to issue NMEA commands or queries to
the MBX-4, each sentence is appended automatically with a <CR> <LF>
when the send button is depressed. This software utility is available for
download from Hemisphere GPS’ Web site at:
www.hemispheregps.com.
Table 4-1: NMEA Message Elements
Element Description
$GP Message Identifier Indicating a GPS Related Message
YYY Type of GPS Message
Xxx Variable Length Message Fields
<CR> Carriage Return
<LF> Line Feed