Garmin GPS 12XL Owner's Manual (Software Version 4.0 and above) - Page 52

REFERENCE DGPS The baud rate is selectable for all RTCM and NMEA interface options. Alert messages will signal any problems with DGPS operation. Interface Setup: DGPS (continued) To enter a DGPS beacon frequency: 1. Highlight the 'FREQ' field, and press . 2. Enter the desired frequency, and press . 3. Highlight the 'RATE' field, and press . 4. Select the desired bit rate (bps), and press . Note: The frequency and bit rate fields are disabled when the 'RTCM/NONE' option is selected. When the GPS 12XL is receiving DGPS corrections from the GBR 21, the 'BEACON RECVR' section of the I/O setup page will display the beacon frequency and signal strength, as well as the distance from the beacon transmitter to your present position. At the bottom of the beacon receiver field, a status message will keep you informed of DGPS activity: • A 'Tuning' message will be displayed while a beacon receiver is selecting a frequency/bit rate and waiting for signal reception. • Once a valid beacon signal has been received, a 'Receiving' message will be displayed. • If the beacon signal is received and no correction data is being received, a 'No Data' message will be displayed. • If a beacon frequency cannot be tuned and/or no signal is received, a 'No Status' message will be displayed. The message page will alert you to any problems relating to DGPS operation. You may also monitor the DGPS status from the status field on the interface page. The GPS12XL will display one of three alert messages concerning DGPS operation: No DGPS Position- there is not enough correction data available to compute a DGPS position. No RTCM Input- the beacon receiver is not properly connected, the baud rates do not match or no signal is being provided. RTCM Input Failed- DGPS data was being received but has been lost. 48