Garmin GNS 480, Installation Manaul

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Installation Procedures
2-4 560-0982-01 Rev L GNS 480 (CNX80) Installation Manual
2.5.2 Existing Sensors
When the GNS 480 is installed with external sensors, these sensors must be installed in accordance with
the manufacturer's data. This manual does not provide information for the installation of specific external
sensors.
The GNS 480 can accept data from multiple altitude, heading, and baro correction sources. If multiple
sources are used, the GNS 480 will accept data as described below.
2.5.2.1 Multiple Altitude Sources
The GNS 480 can accept altitude from an RS-232 altitude encoder, fuel/air data computer (FADC),
ARINC 429 air data computer (ADC), an SL70/SL70R transponder, a GTX 33/330 transponder, and
another GNS 480.
If multiple sources of altitude data are supplied to the GNS 480, only valid data from the highest priority
source is used (input priority cannot be configured). If the highest priority source becomes unavailable,
data is taken from the next-highest priority source. The priorities of the altitude sources are as follows
(from highest to lowest):
1. ARINC 429 ADC
2. FADC
3. RS-232 Altitude Encoder
NOTE
Although the GNS 480 can be configured to accept data from an RS-232 altitude encoder
on different ports, the GNS 480 cannot accept data from two RS-232 altitude encoders.
4. SL70/SL70R Transponder or GTX 33/330 Transponder that receives Gray code altitude.
NOTE
Altitude data received from a second GNS 480 will also be derived from one of the above
sources. Data received on the GNS 480 cross-talk input is treated as if it is received
directly from the source that is supplying altitude to the second GNS 480. If the direct
input and the GNS 480 cross-talk input have the same priority, data from the direct input
is used.
NOTE
Not all models listed in Appendix C.2 are approved for use as an altitude source for
transponders. When configuring the GNS 480 to provide altitude data to a transponder,
only devices approved in accordance with 14 CFR 91.217 may be used.
2.5.2.2 Multiple Heading Sources
The GNS 480 can accept heading from an ARINC 429 Heading Source, an FADC or an XYZ synchro
source. If multiple sources of heading data are supplied to the GNS 480, only valid data from the highest
priority source is used (input priority cannot be configured). If the highest priority source becomes
unavailable, data is taken from the next-highest priority source. The priorities of the heading sources are as
follows (from highest to lowest):
1. XYZ Synchro
2. ARINC 429 Heading Source
3. FADC