Avidyne IFD540 Pilot's Manual page 26

Frequency List
The "FREQ" function key along the right edge of the bezel has
three tabs along the top edge of the page:
 Airport – the most logical com frequencies (e.g.
ATIS, ASOS, AWOS, CTAF, Tower, Ground,
Clearance Delivery, etc) associated with the origin
airport and then when airborne and more than
5nm from the origin, the destination airport;
 Enroute – the most likely enroute ARTCC and
other enroute com frequencies (e.g. FSS) for the
current geographic position;
 Recent – a running list of the com frequencies that
had been selected for the Active frequency slot
within a given power cycle.
Freq List Page
Each additional press of the "FREQ" function key will cycle to the
next top tab. The top tabs can also be touched to activate that
specific list. The tabs only populate when there is a GPS position.
When a desired frequency has been located in the list, it can be
placed into the #1 Standby slot by either double tapping it via
touch or pushing the bottom right dual concentric push knob.
1-20 System Overview