Recommended models are ( Mass Storage mode must be deactivated and interface set to GARMIN with older units and Garmin Spanner with newer ones): Receivers that only operate in Mass Storage mode while connected can not provide real-time positioning (please refer to Garmin Spanner mode) nevertheless the last position, while the receiver was not connected, is stored inside the unit and can be read. All Garmin USB GPS units using the proprietary Garmin PVT protocol (untested with serial devices using a serial to USB converter) are supported and provide real-time positioning. When a GPS unit is connected to the Mac, you can transfer the coordinates and altitude given by the device. To use a Garmin GPS in Mercury Venus Transit Maestro you first have to setup its communication interface.
