Garmin GPSMAP 230 - Manual (Page 76)

Using NMEA & DGPS Interface Settings
If you are using an NMEA interface format, the NMEA format must be specified
in the NMEA format field that will automatically appear when an NMEA option is
selected. The appropriate baud rate will be set automatically.
To select an NMEA format:
1. Select a NMEA IN/OUT format from the options page.
2. Highlight the NMEA Format field and press T .
3. Select a NMEA sentence format and press T .
4. The baud rate will automatically be set to the appropriate speed. If you have selected an
NMEA IN/OUT setting, you must use the same NMEA format for both the input and out-
put device.
Tuning DGPS Stations
If the I/O Format is set to accept RTCM input/NMEA Output for connecting a
differential-ready GPS beacon receiver, you will need to tune a frequency in the
tuning field and select a bit rate. The default frequency will be 304.0 kHz, with a
bit rate of 100 bps, or the last DGPS frequency/bit rate selected.
To tune a DGPS frequency:
1. Select the ‘RTCM In/NMEA Out’ format from the options page.
2. Highlight the beacon receiver frequency field and press T .
3. Enter the desired frequency and press T . If you are using an automatically-tuned
DGPS receiver, you may enter 000.0 for the frequency.
4. Press T to select a bit rate. Five bit rates are available: 0 (used for automatically-
tuned DGPS receivers), 25, 50, 100 and 200 bps. Press T to confirm. The DGPS status,
along with the signal-to-noise ratio of the tuned station, will be displayed at the bottom
of the page.
A. Select the desired format from the NMEA field.
The baud rate will automatically be set to the
appropriate speed.
B. After entering a DGPS frequency, set the bit rate
to the speed indicated on the USCG station chart.
DGPS coverage, frequencies, and bit rates are
available from the Coast Guard’s automated
FAX service (703-313-5920).
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SETUP MENUS
NMEA & DGPS Setup
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