SECTION THREE - InterfacingPage 48 951/952 INSTALLATION MANUAL Revision BSetting the NMEA0183 checksumCertain older devices may not accept sentences containing the NMEA0183 checksum that’s output by the 951 or 952. In such cases, the devicemay not operate properly, if at all. If you encounter difficulty when inter-facing to older equipment, the unit offers the flexibility of turning off theNMEA 0183 checksum.1. At the PORT 1 SETUP or PORT 2 SETUP screen, press the &856253$' to highlight the NMEA 0183 CHECKSUMS option, then pressthe (',7 menu key.2. Press the &85625 3$' to change the setting from 21 to 2))andpress the (17(5key when done.Selecting anindependent NMEAoutput-port datumYou can adjust output position for NMEA 0183 ports 1 and 2 to specificgeodetic datums, independently of the datum you choose for positionaldisplay.1. At the PORT SETUP 1 or PORT SETUP 2 screen, highlight the OUT-PUT DATUM option, then press the (',7 menu key.2. Scroll through the choices using the &856253$'down to makeyour selection. To apply this chosen datum to your lat/lon coordi-nates in the NMEA 0183 output sentences, press the(17(5key.Connecting to other equipmentConnecting to otherNorthstar unitsTwo 951, 952, or 941 units can be connected in order to take advantageof the waypoints/routes sharing feature. This convenient feature lets allwaypoints and routes be transferred between any combination of two ofthese units.Using this feature involves three main steps, which you should performin the following order:1. Check that each unit you want to share waypoints and routes with isoperating with software version 3.12 or higher. To determine theunits’ current software version, press the 67$5 key until you displaythe USER CUSTOMIZATION screen is, then press the 6(59,&(,1)250$7,21 key to display the SERVICE INFORMATION screen.The MAIN BOARD SOF VER field displays the current software ver-sion. If this version is earlier than 3.12, you must upgrade this unit toversion 3.12 before it can share waypoints and routes with anotherNOTE:There is no standard for identifying how numbers should beassigned when converting waypoints from names to numbers.When you export waypoint information as numbers to aperipheral device, be aware that numbers aren’t sequentiallydefined and may be re-used on a random basis.