Eagle Electronics and Lowrance Electronics have information on their GPS (and other) products, including manuals for several models in .pdf format. The Eagle site has a document describing the serial interface protocol used to communicate with Eagle/Lowrance products. Lowrance has an ocx on their web site for interfacing to almost all of their gps units, includes a lot of control for tracks and routes.
One user reports that firmware in the Lowrance GlobalMap GPS is field-upgradable. You can order a cartridge from Lowrance for US$40 and insert it in one of the map cartridge sockets, then place the receiver in a special mode to transfer the data from the cartridge to the GPS. You can then return the cartridge for credit, making the upgrade essentially free. (The same may apply to other models - worth asking...)
accunav.txt (15758 bytes) is a review of the Eagle Accunav Sport, and Eagle's waypoint managment software, by Dave Fortner (fortner@conan.ids.net)
EENavigator (Oct. 28/97, 3,397,523 bytes) is a visual basic application that was written for the Eagle Explorer. EE Navigator currently provides you with 4 panels. The first panel, General Info, queries your GPS for it's system information, the firmware level, number of available waypoints, routes, etc. The second panel displays the RMC/NMEA from your receiver which is the 'Recommended Minimum Specific GPS/Transit Data'. This data consist of, among other things, your current position, time, date, and speed of travel. The third panel displays the RMB/NMEA from your receiver, 'Recommended Minimum Navigation Information'. This panel displays information related to navigating to a particular waypoint, such as destination position, bearing, distance, etc. The fourth panel is for viewing, adding, and deleting waypoints.
G7To and G7ToWin convert GarDown7 download files to Street Atlas 3 format, or vice versa, and converts either format to formats compatible with PROJ.EXE, NAD2NAD.EXE, or UTMS.EXE. This version can also communicate directly with a Garmin or Lowrance receiver.
This picture shows the connections between an Eagle 6 pin connector and a DE-9 serial port connector
