Garmin 010-11018-00 GPS 20x Technical Specifications - Page 10

3 GPS 20x SOFTWARE INTERFACE The GPS 20x transmits using the Garmin USB interface. The Garmin USB interface is discussed in the Garmin Device Interface Specification found in the Garmin Device Interface SDK located on the Garmin Web site at: www.garmin.com/support/commProtocol.html. You can configure the GPS 20x to transmit binary data information over the USB interface. Refer to Appendix B: Garmin Binary Output Format. 3.1 TRANSMITTED NMEA 0183 SENTENCES The following paragraphs define the sentences that can be transmitted by the GPS 20x using Spanner (an application that can provide NMEA output via a virtual COM port). Spanner is available for free on the Garmin web site. To download the software, start at www.garmin.com/oem, select the GPS 20x, and then select Updates & Downloads. 3.1.1 Sentence Transmission Rate Sentences are transmitted with respect to the user selected baud rate. The GPS sensor will transmit each sentence once per second. The sentences are not configurable. Sentence Maximum Characters GPRMC 74 GPGGA 82 GPGSA 66 GPGSV 70 PGRMT 50 Table 1: NMEA 0183 Output Sentence Order and Size The maximum number of fields allowed in a single sentence is 82 characters including delimiters. Values in the table include the sentence start delimiter character "$" and the termination delimiter . 190-00880-00 GPS 20x Technical Specifications Page 7 Rev. A