Garmin GPS 18x Technical Specifications - Page 19

4.2 TRANSMITTED NMEA 0183 SENTENCES The subsequent paragraphs define the sentences that can be transmitted by the GPS 18x PC and LVC. 4.2.1 Sentence Transmission Rate Sentences are transmitted with respect to the user selected baud rate. The GPS sensor will transmit each sentence (except where noted in particular transmitted sentence descriptions) at a periodic rate based on the user selected baud rate and user selected output sentences. The GPS sensor will transmit the selected sentences contiguously. The length of the transmission can be determined by the following equation and Tables 2 and 3: length of transmission = total characters to be transmitted characters transmitted per second Sentence GPRMC GPGGA GPGSA GPGSV Output by Default?     (PC and LVC only) Maximum Characters 74 82 66 70 PGRME 35 GPGLL 44 GPVTG  (18x-5Hz) 42 PGRMV 32 PGRMF 82 PGRMB 40 PGRMM PGRMT Once per minute 50 Table 2: NMEA 0183 Output Sentence Order and Size Baud Characters per Second 4800 480 9600 960 19200 1920 38400 3840 Table 3: Characters per Second for Available Baud Rates 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 . For the GPS 18x PC and LVC, the factory set defaults result in a once per second transmission at the NMEA 0183 specification transmission rate of 4800 baud. For the GPS 18x-5Hz, the factory set defaults will result in a five times per second transmission at 19200 baud. For the GPS 18x LVC: Regardless of the selected baud rate, the information transmitted by the GPS sensor is referenced to the one-pulse-per-second output pulse immediately preceding the GPRMC sentence, or whichever sentence is output first in the burst (see Table 2 above). For the GPS 18x-5Hz: Regardless of the selected baud rate, the information transmitted by the GPS sensor is referenced to the preceding five-times-per-second output pulse. The GPS 18x USB can use Spanner (an application that can provide NMEA output via a virtual COM port) to receive the same default NMEA sentences as the GPS 18x PC and LVC at a rate of once per second. Spanner is available for free on the Garmin web site. To download the software, start at www.garmin.com/oem, select the GPS 18x USB, and then select Updates & Downloads. 190-00879-08 GPS 18x Technical Specifications Page 15 Rev. B