Is it necessary feed separate pressure altitude information to the IIMorrow MX20 if it is already being fed to the GX GPS that is interfaced to the MX20?
No. Pressure altitude can be passed to the MX20 through the GX series of GPS units’ serial data stream. This feature allows one of the four MX20 serial ports to be freed for other purposes than a dedicated altitude encoder input. For this feature to function, the GX GPS muse be running version 3.2 or newer software. In addition, the GX GPS must be wired and configured for altitude input from an altitude encoder. The GX serial output should be set to ‘extended’ mode for the altitude to be included in the data stream sent to the MX20. The altitude source port on the MX20 should be set to the same port that the GX GPS is connected to.
