For a direct connect to the D3/2/300/200/100 one needs a GPS with an RS-232 serial port that either goes to 9 pin D sub connector to the Nikon 10 pin plug and the GPS needs to send NMEA code at 4800 baud, there is no hardware or software hand shacking.

Note: this serial port is not the same as the USB port on most GPS units, this is a 3 or 4 wire port and most GPS units do not have it. Be very careful when reading the specifications of a GPS unit or getting information from a salesperson or customer support.

One can also record tracks or waypoints on the GPS and then transfer that data to the computer and add the GPS by use of software to the images. This option would also provide for the use of more than one camera at a time. This also eleminates the need for a connected GPS unit and the extra weight around the neck.

George
My Nikonian Galleries