Altitude Reporting Mode is normally selected automatically when the aircraft is on the ground or airborne. Altitude Reporting Mode can also be selected manually by touching the ALT Button. When Altitude Reporting Mode is selected, an ALT indication will appear on the Transponder Datafield Button. Selecting Altitude Reporting Mode enables transmission of transponder replies and squitters. Transmissions will include pressure altitude information. The ALT indication and transponder code on the Transponder Datafield Button will appear green while airborne and white while on the ground. When the transponder is operating with an air state of on-ground it will disable replies to Mode A, Mode C, and Mode S all-call interrogations so the aircraft will not show up on the traffic systems of other aircraft.