Garmin GPS 12CX Owner's Manual

Also see for GPS 12CX: Specifications

Garmin GPS 12CX Owner's Manual Manual pdf 50 page image

42Transfer Mode FieldI/O Format FieldInterface Setup SubmenuP a g eREFERENCEMain Menu—Interface SetupSubmenuInterface SetupThe GPS 12CX’s interface page lets you specify theformats for connecting external devices. There are sixoptions: GRMN/GRMN, None/None, RTCM/None,RTCM/NMEA, NMEA/NMEA, and None/NMEA. Eachoption lists the input format first, followed by the outputformat.To select an I/O format:1. Highlight the I/O field and pressENTER.2. Select the desired setting and pressENTER.The GRMN/GRMN setting is a proprietary formatthat lets you exchange information such as waypoints,routes, and track logs between two GARMIN GPS unitsor the GPS 12CX and a PC. The transfer mode field isdirectly below ‘GRMN/GRMN’, and allows you to specifywhat information to request or send to a second GPSunit. The ‘Host’ setting lets you control all data transferfunctions from the second GPS unit or a PC.To select a transfer mode:1. Highlight the transfer mode field and pressENTER.2. Select a desired setting, and pressENTER.To disable all interfacing capabilities, select the ‘None/None’ setting. If you want to output NMEA data withoutany differential input capability, select ‘None/NMEA’.Interface Setup: DGPSThe last two format settings allow the differential-ready GPS 12CX to accept RTCM DGPS corrections inRTCM 104 version 2.0 format. Using DGPS correctionswill improve receiver accuracy to 1-5 meters, regardlessof errors induced by the U.S. Dept. of Defense SelectiveAvailability (SA) program. Two RTCM options are avail-able: ‘RTCM/NONE’, which allows connection to a bea-con receiver with no output capability; and ‘RTCM/NMEA’, which allows DGPS input and NMEA output.When ‘RTCM/NMEA’ is selected, the GPS 12CX willeither automatically try to tune the last frequency and bitrate you selected or will switch to the default frequency of304.0 kHz with a bit rate of 100 bps if no previous beaconhas been tuned. (You may also enter your own frequencyand bit rate if desired.) This information is used to tune/control an optional GARMIN GBR 21 differential beaconreceiver.Note: Use the ‘RTCM/NONE’ setting if your beaconreceiver does not support these software-driven controls.