Nmea And Dgps Setup; Using Nmea And Dgps Interface Settings; Tuning Dgps Stations; To Tune A Dgps Frequency - Garmin GPSMAP 235 Sounder Owner's Manual

Using NMEA and 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. See page 96 for a list
of NMEA supported sentences.
To select a 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 select-
ed an NMEA IN/OUT setting, you must use the same NMEA format for both the input
and output 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 is 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 . If you are using an automatically-tuned DGPS receiver, you
quency and press
can enter 000.0 for the frequency.
T to select a bit rate. Five bit rates are available: 0 (used for automatically-
3. Press
tuned DGPS receivers), 25, 50, 100 and 200 bps. Press
status, along with the signal-to-noise ratio of the tuned station, will be displayed at
the bottom of the page.
T . Enter the desired fre-
T to confirm. The DGPS
GETTING START-
SETUP MENUS
ED

NMEA and DGPS Setup

Using the GOTO
Key
A B
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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