AIR Traffic devices can be connected to many systems via a so-called ARINC429 interface, e.g. GARMIN G1000, GTN or GNS, Avidyne IFD, and others.
Due to a peculiarity of the ARINC429 format and the fact that the AT-1 can only determine the direction of traffic when its own aircraft is moving (and thus a GPS track is available), no traffic data is displayed by default when the aircraft is stationary.
In the AT-1 setup (Advanced/Expert) there is a parameter called GPS Track Fallback.
This parameter controls what reference in terms of direction traffic data should have in the AT-1 when there is no GPS track (i.e. no movement or no GPS reception).
By default, this parameter is set to show no traffic on the ground via ARINC429.
An alternative is to set the parameter to "TRUENORTH". Then the reference for traffic data at a standstill is always true north. Due to the fact that the own aircraft is seldom always parked with the nose to the north, the directions of the traffic data displayed in standstill are then no longer "correct", but are rotated by the deposit to true north.