Garmin GNS 480 User manual

GNS 480 (CNX80)
Color GPS/Nav/Com
Installation Manual
September 2004
560-0982-01 Rev A

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GNS 480 (CNX80) Installation Manual560-0982-01 Rev A i
HISTORY OF REVISIONS
Revision Date Description
-- 07/13/04 Initial release.
A 9/15/04 Regulatory compliance clarification.
ORDERING INFORMATION
To receive additional copies of GNS 480 publications, order the following part numbers:
GNS 480 Installation Manual 560-0982-xx
GNS 480 Pilot Guide 560-0984-xx
GNS 480 Reference Guide 560-0989-xx
GNS 480 Quick Reference Guide 561-0281-xx
GNS 480 Computer-Based Training 560-0990-xx
A-33 GPS Antenna Installation Guide 560-0949-xx
A-34 GPS Antenna Installation Guide 560-5047-xx

ii 560-0982-01 Rev A- GNS 480 (CNX80) Installation Manual
List of Effective Pages
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Table of Contents
GNS 480 (CNX80) Installation Manual560-0982-01 Rev A iii
TABLE OF CONTENTS
1GENERAL INFORMATION................................................................................................................................. 1-1
1.1 ABOUT THIS MANUAL .................................................................................................................................. 1-1
1.1.1 MANUAL ORGANIZATION......................................................................................................................... 1-1
1.1.2 SCOPE ...................................................................................................................................................... 1-1
1.2 EQUIPMENT DESCRIPTION............................................................................................................................. 1-2
1.2.1 FEATURES ................................................................................................................................................ 1-2
1.2.2 SYSTEM INTERFACES ............................................................................................................................... 1-3
1.3 SPECIFICATIONS ............................................................................................................................................ 1-6
1.3.1 ELECTRICAL............................................................................................................................................. 1-6
1.3.2 PHYSICAL................................................................................................................................................. 1-6
1.3.3 ENVIRONMENTAL..................................................................................................................................... 1-6
1.3.4 DISPLAY................................................................................................................................................... 1-7
1.3.5 GPS/WAAS RECEIVER PERFORMANCE................................................................................................... 1-7
1.3.6 COMM RECEIVER PERFORMANCE ............................................................................................................ 1-8
1.3.7 COMM TRANSMITTER PERFORMANCE...................................................................................................... 1-8
1.3.8 NAV RECEIVER PERFORMANCE .............................................................................................................. 1-9
1.3.9 AVIONICS INTERFACES........................................................................................................................... 1-10
1.3.10 ANTENNA REQUIREMENTS ................................................................................................................ 1-12
1.3.11 SERIAL INTERFACE............................................................................................................................ 1-14
1.4 REGULATORY COMPLIANCE........................................................................................................................ 1-14
1.4.1 TSO/JTSO AND ADVISORY CIRCULAR REFERENCES ............................................................................. 1-14
1.4.2 TSO/JTSO AUTHORIZATION.................................................................................................................. 1-15
1.4.3 FCC GRANT OF EQUIPMENT AUTHORIZATION ....................................................................................... 1-15
1.4.4 GNS 480 STC AUTHORIZATION............................................................................................................. 1-15
1.5 DATABASE UPDATES .................................................................................................................................. 1-15
1.6 UNPACKING THE EQUIPMENT...................................................................................................................... 1-16
1.7 PACKAGE CONTENTS .................................................................................................................................. 1-17
1.8 LICENSE REQUIREMENTS ............................................................................................................................ 1-18
1.9 DEFINITIONS &ACRONYMS ........................................................................................................................ 1-19
2INSTALLATION ................................................................................................................................................. 2-1
2.1 PRE-INSTALLATION INFORMATION................................................................................................................ 2-1
2.2 INSTALLATION OVERVIEW ............................................................................................................................ 2-1
2.3 MATERIALS NOT SUPPLIED........................................................................................................................... 2-1
2.3.1 MATERIALS REQUIRED BUT NOT SUPPLIED ............................................................................................. 2-1
2.3.2 OPTIONAL ACCESSORIES NOT SUPPLIED .................................................................................................. 2-2
2.4 SPECIAL TOOLS REQUIRED ........................................................................................................................... 2-2
2.5 INSTALLATION CONSIDERATIONS.................................................................................................................. 2-2
2.5.1 MINIMUM SYSTEM CONFIGURATION ........................................................................................................ 2-2
2.5.2 EXISTING SENSORS .................................................................................................................................. 2-4
2.5.3 MOUNTING CONSIDERATIONS .................................................................................................................. 2-5
2.5.4 CABLING AND WIRING ............................................................................................................................. 2-8
2.5.5 AIR CIRCULATION AND COOLING ............................................................................................................. 2-8
2.5.6 COMPASS SAFE DISTANCE ....................................................................................................................... 2-8
2.5.7 VIEWING ANGLE ...................................................................................................................................... 2-8
2.5.8 HELICOPTER INSTALLATION..................................................................................................................... 2-8
2.6 EQUIPMENT MOUNTING................................................................................................................................2-9
2.6.1 MOUNTING TUBE INSTALLATION ............................................................................................................. 2-9
2.6.2 UNIT INSERTION..................................................................................................................................... 2-12
2.6.3 UNIT REMOVAL ..................................................................................................................................... 2-13
2.6.4 UNIT REPLACEMENT .............................................................................................................................. 2-13
2.7 ELECTRICAL CONNECTIONS ........................................................................................................................ 2-15
2.7.1 INTERFACE CONNECTOR DEFINITION ..................................................................................................... 2-16
2.8 FUNCTIONAL DESCRIPTIONS ....................................................................................................................... 2-23
2.8.1 POWER................................................................................................................................................... 2-23

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iv 560-0982-01 Rev A GNS 480 (CNX80) Installation Manual
2.8.2 MAIN COURSE DEVIATION INDICATOR ...................................................................................................2-23
2.8.3 AUXILIARY COURSE DEVIATION INDICATOR ..........................................................................................2-25
2.8.4 COMPOSITE INDICATOR ..........................................................................................................................2-26
2.8.5 ALTIMETER ............................................................................................................................................2-26
2.8.6 SYNCHRO HEADING................................................................................................................................2-26
2.8.7 ANNUNCIATOR OUTPUTS........................................................................................................................2-27
2.8.8 DISCRETE OUTPUTS................................................................................................................................2-30
2.8.9 SWITCHES /DISCRETE INPUTS ................................................................................................................2-31
2.8.10 SERIAL INTERFACES ..........................................................................................................................2-32
2.8.11 TIME MARK OUTPUT .........................................................................................................................2-37
2.8.12 VHF COM..........................................................................................................................................2-37
2.8.13 VHF NAV ..........................................................................................................................................2-38
2.8.14 MESSAGE AUDIO ...............................................................................................................................2-39
2.8.15 RMI /OBI .........................................................................................................................................2-39
2.8.16 DME TUNING ....................................................................................................................................2-40
2.9 ANTENNA INSTALLATION AND CONNECTIONS .............................................................................................2-41
2.9.1 COMM ANTENNA....................................................................................................................................2-41
2.9.2 GPS ANTENNA .......................................................................................................................................2-41
2.9.3 NAV ANTENNA......................................................................................................................................2-42
2.10 WEIGHT AND BALANCE...............................................................................................................................2-43
2.11 ELECTRICAL LOAD ANALYSIS .....................................................................................................................2-43
3POST INSTALLATION CONFIGURATION &CHECKOUT PROCEDURES............................................................3-1
3.1 MOUNTING AND WIRING CHECK ...................................................................................................................3-1
3.2 EQUIPMENT SETUP AND CONFIGURATION .....................................................................................................3-1
3.2.1 SETUP FUNCTION......................................................................................................................................3-2
3.3 EQUIPMENT OPERATIONAL/FUNCTIONAL TEST ...........................................................................................3-19
3.3.1 GNS 480 CHECKOUT UTILITIES..............................................................................................................3-19
3.3.2 SYSTEM CHECKOUT –GROUND CHECKS................................................................................................3-30
3.3.3 SYSTEM CHECKOUT –FLIGHT CHECKS ..................................................................................................3-41
3.4 DATABASE CHECK ......................................................................................................................................3-42
3.4.1 DATA CARD REPLACEMENT ...................................................................................................................3-42
4TROUBLESHOOTING .........................................................................................................................................4-1
4.1 TROUBLESHOOTING PROCEDURE ..................................................................................................................4-1
4.2 CONTACTING THE FACTORY FOR ASSISTANCE ..............................................................................................4-4
5LIMITATIONS ....................................................................................................................................................5-1
5.1 OPERATION ...................................................................................................................................................5-1
5.2 INSTALLATION...............................................................................................................................................5-1
5.2.1 GPS ANTENNA .........................................................................................................................................5-1
5.2.2 ANTENNA INSTALLATION –GENERAL ......................................................................................................5-1
5.2.3 EQUIPMENT INTERFACED TO THE GNS 480..............................................................................................5-1
5.2.4 PRESERVATION OF PREVIOUS SYSTEMS....................................................................................................5-2
5.3 AIRCRAFT RADIO STATION LICENSE..............................................................................................................5-2
6PERIODIC MAINTENANCE ................................................................................................................................6-1
6.1 EQUIPMENT CALIBRATION ............................................................................................................................6-1
6.2 VOR CHECKS ...............................................................................................................................................6-1
6.3 CLEANING .....................................................................................................................................................6-1
6.4 BATTERY REPLACEMENT ..............................................................................................................................6-1
6.5 DISPLAY BACKLIGHT.....................................................................................................................................6-1
APPENDIX A -CERTIFICATION DATA...................................................................................................................A-1
A.1 ENVIRONMENTAL QUALIFICATION ...............................................................................................................A-1
A.2 GNS 480 STC DATA....................................................................................................................................A-2
APPENDIX B -SERIAL INTERFACE SPECIFICATIONS ........................................................................................... B-1
B.1 SERIAL INPUT SPECIFICATIONS.....................................................................................................................B-1

Table of Contents
GNS 480 (CNX80) Installation Manual560-0982-01 Rev A v
B.1.1 ALTITUDE ENCODER/CONVERTER INPUT ................................................................................................ B-2
B.1.2 FUEL/AIR DATA COMPUTER INPUT ......................................................................................................... B-4
B.2 SERIAL OUTPUT SPECIFICATIONS ................................................................................................................. B-7
B.2.1 MAPCOM OUTPUT................................................................................................................................... B-7
APPENDIX C -EQUIPMENT COMPATIBILITY ....................................................................................................... C-1
C.1 ALTITUDE SOURCES..................................................................................................................................... C-1
C.2 FUEL/AIR DATA COMPUTERS ...................................................................................................................... C-1
C.3 HEADING SOURCES...................................................................................................................................... C-2
C.4 ALTIMETERS FOR BARO CORRECTION ......................................................................................................... C-2
C.5 AUTOPILOTS ................................................................................................................................................ C-2
C.6 ELECTRONIC HSI’S...................................................................................................................................... C-3
C.7 TRAFFIC ADVISORY SYSTEMS...................................................................................................................... C-3
APPENDIX D -INTERCONNECT DIAGRAMS .......................................................................................................... D-1
APPENDIX E -ACCEPTABLE AIRCRAFT BY EVALUATION................................................................................... E-1
APPENDIX F –OPTIONAL ACCESSORIES NOT SUPPLIED......................................................................................F-1
F.1 CDI/HSI SOURCE SELECTION ANNUNCIATORS.............................................................................................F-1
LIST OF TABLES
TABLE 1-1 -TSO AUTHORIZATION ......................................................................................................... 1-15
TABLE 1-2 -JTSO AUTHORIZATION ....................................................................................................... 1-15
TABLE 1-3 -PACKAGE CONTENTS ........................................................................................................... 1-17
TABLE 1-4 -INSTALLATION KIT CONTENTS (PN 424-2014-800)............................................................. 1-17
TABLE 1-5 –HARDWARE KIT CONTENTS (P/N 424-2016-000) ............................................................... 1-18
TABLE 1-6 -OPTIONAL EQUIPMENT AVAILABLE FROM GARMIN AT...................................................... 1-18
TABLE 2-1 -CRIMP TOOL FOR P/N 162-0082 ............................................................................................ 2-2
TABLE 2-2 -CRIMP TOOL FOR P/N 245-0027 ............................................................................................ 2-2
TABLE 2-3 -INTERFACE CONNECTORS .................................................................................................... 2-15
TABLE 2-4 -CRIMP CONTACT SPECIFICATIONS ....................................................................................... 2-15
TABLE 2-5 MAIN SYSTEM CONNECTOR PIN-OUT (P1) ........................................................................... 2-17
TABLE 2-6 COM I/O CONNECTOR PIN-OUT (P4).................................................................................... 2-18
TABLE 2-7 I/O EXPANSION CONNECTOR PIN-OUT (P5).......................................................................... 2-19
TABLE 2-8 NAV I/O CONNECTOR PIN-OUT (P7) .................................................................................... 2-22
TABLE 2-9 -ARINC 429 INPUT LABELS .................................................................................................. 2-34
TABLE 2-10 -ARINC 429 OUTPUT LABELS............................................................................................ 2-35
TABLE 2-10A11 -ARINC 429 OUTPUT LABELS –CONFIGURATION 5(ARINC 743A).......................... 2-37
TABLE 2-12 -UNIT WEIGHTS .................................................................................................................. 2-43
TABLE 2-13 -UNIT POWER LOADS.......................................................................................................... 2-43
TABLE 3-1 -SERIAL PORT SETUP CONFIGURATIONS ................................................................................. 3-3
TABLE 3-2 -ARINC 429 INPUT AND OUTPUT PORT SETTINGS.................................................................. 3-4
TABLE 3-3 –GTX RS-232 SERIAL PORT SETTINGS................................................................................. 3-12
TABLE 3-4 –GTX ARINC 429 INPUT AND OUTPUT PORT SETTINGS...................................................... 3-13
TABLE 3-5 –LAMP OUTPUT TEST ITEMS ................................................................................................. 3-23
TABLE 3-6 –DESCRIPTION OF INPUT MONITOR ITEMS ............................................................................ 3-29
TABLE 3-7 -GNS 480 POST-INSTALLATION CHECKOUT LOG.................................................................. 3-43
TABLE 4-1. TROUBLESHOOTING GUIDE ..................................................................................................... 4-1
TABLE B- 1-RS-232 SERIAL INPUT (RX) SELECTIONS ........................................................................... B-1
TABLE B- 2-ALTITUDE INPUT DATA....................................................................................................... B-2
TABLE B- 3-FUEL/AIR DATA MESSAGE DATA (S FORMAT)................................................................... B-4
TABLE B- 4-FUEL/AIR DATA MESSAGE DATA (Z FORMAT) .................................................................. B-6

Table of Contents
vi 560-0982-01 Rev A GNS 480 (CNX80) Installation Manual
TABLE B- 5-RS-232 SERIAL OUTPUT (TX) SELECTIONS ........................................................................B-7
TABLE B- 6-MOVING MAP ASCII NAVIGATION DATA...........................................................................B-8
TABLE B- 7-MOVING MAP BINARY ROUTE DATA..................................................................................B-9
TABLE B- 8-NEAREST WAYPOINT LIST DATA ......................................................................................B-10
TABLE B- 9-FLIGHT PLAN WAYPOINT TYPE......................................................................................... B-11
LIST OF ILLUSTRATIONS
FIGURE 1-1 -GNS 480 COLOR GPS/NAV/COM..........................................................................................1-2
FIGURE 1-2 -SAMPLE SINGLE GNS 480 SYSTEM DIAGRAM ......................................................................1-3
FIGURE 1-3 -SAMPLE DUAL GNS 480 SYSTEM DIAGRAM.........................................................................1-4
FIGURE 2-1 –ACCEPTABLE FIELD-OF-VIEW ..............................................................................................2-6
FIGURE 2-2 –ACCEPTABLE CDI/HSI SOURCE SELECTION ANNUNCIATION AREA....................................2-7
FIGURE 2-3 -GNS 480 DIMENSIONS........................................................................................................2-11
FIGURE 2-4 -TYPICAL MOUNTING RACK .................................................................................................2-12
FIGURE 2-5 -CAM LOCK POSITIONING.....................................................................................................2-13
FIGURE 2-6 -MOUNTING FRAME ASSEMBLY ...........................................................................................2-14
FIGURE 2-7 -REAR MOUNTING TUBE CONNECTOR LAYOUT...................................................................2-16
FIGURE 2-8 -37-PIN CONNECTOR.............................................................................................................2-17
FIGURE 2-9 -15-PIN CONNECTOR.............................................................................................................2-18
FIGURE 2-10 -78-PIN CONNECTOR DETAIL..............................................................................................2-21
FIGURE 2-11 -REAR COAX CONNECTOR ASSEMBLY ...............................................................................2-42
FIGURE 2-12 -GNS 480 CENTER OF GRAVITY ........................................................................................2-44
FIGURE 3-1 -GROUND MAINTENANCE MODE DISPLAY.............................................................................3-2
FIGURE 3-2 -SERIAL PORT SETUP PAGE ....................................................................................................3-2
FIGURE 3-3 -ARINC 429 PORTS SETUP PAGE ...........................................................................................3-4
FIGURE 3-4 -RESOLVER INTERFACE SETUP PAGE......................................................................................3-5
FIGURE 3-5 -RESOLVER CALIBRATION PAGE ............................................................................................3-6
FIGURE 3-6 -ALTIMETER INTERFACE.........................................................................................................3-7
FIGURE 3-7 -BARO-ALTIMETER CALIBRATION..........................................................................................3-7
FIGURE 3-8 -COM RADIO SETUP ................................................................................................................3-8
FIGURE 3-9 -MISCELLANEOUS SETUP ITEMS.............................................................................................3-9
FIGURE 3-10 –MEASUREMENT OF GPS VERTICAL OFFSET.......................................................................3-9
FIGURE 3-11 –GPS VERTICAL OFFSET SETUP PAGE ...............................................................................3-10
FIGURE 3-12 -GTX MAIN SETUP PAGE ...................................................................................................3-11
FIGURE 3-13 –GTX RS-232 SERIAL SETUP PAGE ...................................................................................3-12
FIGURE 3-14 –GTX ARINC 429 SETUP PAGE (GTX 33/330 ONLY)........................................................3-13
FIGURE 3-15 –GTX AIRCRAFT CONFIGURATION SETUP PAGE ...............................................................3-14
FIGURE 3-16 –GTX AUDIO SETUP PAGE (GTX 33/330 ONLY)................................................................3-16
FIGURE 3-17 –GTX DIAGNOSTICS PAGE .................................................................................................3-18
FIGURE 3-18 -TEST MAIN PAGES ...........................................................................................................3-19
FIGURE 3-19 -MAIN CDI FLAG TEST .......................................................................................................3-20
FIGURE 3-20 –AUXILIARY CDI FLAG TEST .............................................................................................3-20
FIGURE 3-21 –MAIN CDI TEST PAGE ......................................................................................................3-21
FIGURE 3-22 –AUXILIARY VDI TEST PAGE.............................................................................................3-22
FIGURE 3-23 -LAMP OUTPUT TEST..........................................................................................................3-23
FIGURE 3-24 -DISPLAY TEST INITIAL SCREEN.........................................................................................3-24
FIGURE 3-25 -BEZEL KEY TEST...............................................................................................................3-25
FIGURE 3-26 -AUTOPILOT TEST...............................................................................................................3-26
FIGURE 3-27 -INTERFACE MONITOR FUNCTION DISPLAY -PAGE 1.........................................................3-27
FIGURE 3-28 -INTERFACE MONITOR FUNCTION DISPLAY -PAGE 2.........................................................3-27
FIGURE 3-29 -INTERFACE MONITOR FUNCTION DISPLAY -PAGE 3.........................................................3-28

Table of Contents
GNS 480 (CNX80) Installation Manual560-0982-01 Rev A vii
FIGURE 3-30 –GPS INFORMATION START-UP SCREEN............................................................................ 3-31
FIGURE 3-31 –GPS STATUS PAGE ........................................................................................................... 3-32
FIGURE B- 1-ALTITUDE DATA INPUT ..................................................................................................... B-3
FIGURE B- 2-FUEL /AIR DATA INPUT (S FORMAT) ................................................................................ B-5
FIGURE B- 3-MOVING MAP DATA OUTPUT.......................................................................................... B-11
FIGURE D- 1-MAIN POWER AND ANTENNA INTERCONNECT DIAGRAM ..................................................D-3
FIGURE D- 2-MAIN COURSE DEVIATION INDICATOR INTERCONNECT DIAGRAM ...................................D-5
FIGURE D- 3-AUXILIARY CDI INTERCONNECT DIAGRAM.......................................................................D-7
FIGURE D- 4-BARO POTENTIOMETER/SYNCRHO HEADING/RMI INTERCONNECT DIAGRAM..................D-9
FIGURE D- 5-RS232 SERIAL INTERFACES INTERCONNECT DIAGRAM...................................................D-11
FIGURE D- 6-GNS 480 TO SL10/15 AUDIO PANEL INTERCONNECT DIAGRAM .....................................D-13
FIGURE D- 7-DME TUNING INTERCONNECT DIAGRAM ........................................................................D-15
FIGURE D- 8-S-TEC AUTOPILOT INTERCONNECT DIAGRAM ................................................................D-17
FIGURE D- 9-CENTURY AUTOPILOT INTERCONNECT DIAGRAM............................................................D-19
FIGURE D- 10 -BENDIX/KING AUTOPILOT INTERCONNECT DIAGRAM...................................................D-21
FIGURE D- 11 -SINGLE GNS 480 FULL STACK INTERCONNECT DIAGRAM ............................................D-23
FIGURE D- 12 -FULL STACK WITH DUAL GNS 480’S INTERCONNECT DIAGRAM ..................................D-25
FIGURE D- 13 -GNS 480 TO SANDEL SN3308 NAV DISPLAY INTERCONNECT DIAGRAM......................D-27
FIGURE D- 14 -GNS 480 TO CDI/HSI SOURCE SELECT ANNUNCIATORS INTERCONNECT DIAGRAM....D-29
FIGURE D- 15 -GNS 480 TO TRAFFIC SYSTEM AND TRANSPONDER INTERCONNECT DIAGRAM ...........D-31

Table of Contents
viii 560-0982-01 Rev A GNS 480 (CNX80) Installation Manual
NOTES

General Information
GNS 480 (CNX80) Installation Manual560-0982-01 Rev A 1-1
1 GENERAL INFORMATION
1.1 ABOUT THIS MANUAL
This manual describes the installation and checkout procedures for the GNS 480 Color GPS/Nav/Com. It
is intended for use by persons certified by the Federal Aviation Administration (FAA) to install avionics
devices.
1.1.1 MANUAL ORGANIZATION
Provides GENERAL INFORMATION about the GNS 480 unit. TSO and JTSO
certification information is also included in this section.
Includes INSTALLATION PROCEDURES.
Includes POST-INSTALLATION CONFIGURATION AND CHECKOUT.
Includes TROUBLESHOOTING information.
Includes LIMITATIONS for the equipment and installation.
Includes PERIODIC MAINTENANCE requirements.
Includes CERTIFICATION DATA.
Includes SERIAL INTERFACE SPECIFICATIONS.
Includes EQUIPMENT COMPATIBILITY information.
Includes INTERCONNECT DIAGRAMS.
Provides a listing of ACCEPTABLE AIRCRAFT BY EVALUATION for those aircraft
that have been evaluated by the FAA.
Provides a listing of OPTIONAL ACCESSORIES NOT SUPPLIED.
1.1.2 SCOPE
The information in this manual is STC approved. Only the equipment interfaces covered in this manual
are within the scope of this STC. Other equipment may be suitable for use with the GNS 480, but use of
such equipment is beyond the scope of this STC – additional FAA approval may be required if equipment
not covered in this manual is used to interface to the GNS 480.
Antenna installation in the pressure vessel of pressurized aircraft is also beyond the scope of the GNS
480 STC. Additional manufacturer's data may be necessary and FAA approval may be required to cover
the installation of the antenna.
Refer to Section 5 Limitations for additional information.
SECTION 1
SECTION 2
SECTION 3
SECTION 4
SECTION 5
SECTION 6
APPENDIX A
APPENDIX B
APPENDIX C
APPENDIX D
APPENDIX E
APPENDIX F

General Information
1-2 560-0982-01 Rev A GNS 480 (CNX80) Installation Manual
1.2 EQUIPMENT DESCRIPTION
The GNS 480 Color GPS/Nav/Com is a panel-mounted product that contains a GPS/WAAS engine, VHF
Comm, and VHF Nav in an integrated unit with a moving map and color display. The GNS 480 will also
control a remote transponder.
Figure 1-1 - GNS 480 Color GPS/Nav/Com
1.2.1 FEATURES
The features of the GNS 480 Color GPS/Nav/Com include:
•10-36 VDC Power Capability
•Sunlight-readable 256-color 3.8" diagonal LCD display
•GPS/WAAS engine for state-of-the-art fast, accurate navigation and precision approach (15-channel,
3 WAAS decoders, 5 Hz update of position, time, and velocity, 1 pps output)
•VHF engine for VOR/LOC/GS navigation
•VHF Com with 760 channels and 8 watts transmit power
•Flexible I/O support for RS232, RS422, and ARINC 429
•Control of a remote transponder
•Audio Messages
•Front panel-accessible data card

General Information
GNS 480 (CNX80) Installation Manual560-0982-01 Rev A 1-3
1.2.2 SYSTEM INTERFACES
The interfaces for a typical single GNS 480 avionics stack are shown in Figure 1-2, while the interfaces
for a typical dual GNS 480 avionics stack are shown in Figure 1-3. The available interfaces are further
described in the following sections.
Figure 1-2 - Sample Single GNS 480 System Diagram

General Information
1-4 560-0982-01 Rev A GNS 480 (CNX80) Installation Manual
Figure 1-3 - Sample Dual GNS 480 System Diagram
1.2.2.1 CDI
The GNS 480 is capable of driving one external course deviation indicator (CDI) with information based
upon VHF Nav or GPS data. The GNS 480 also accepts a resolver input from this CDI. The GNS 480 is
capable of driving a second external CDI with information based upon GPS data.
1.2.2.2 Composite Indicator
The GNS 480 is capable of driving an external composite indicator with information based upon VHF
Nav data.
1.2.2.3 RMI
The GNS 480 is capable of driving an external RMI (or OBI) navigation indicator with a digital clock /
data / sync interface.

General Information
GNS 480 (CNX80) Installation Manual560-0982-01 Rev A 1-5
1.2.2.4 DME
The GNS 480 can channel a DME based upon the tuned VOR frequency. Currently, the GNS 480 only
supports the King Serial DME channeling format.
1.2.2.5 Annunciator Outputs and Switch Inputs
The GNS 480 can drive various external annunciator lamps and receive inputs from various switches to
control the GNS 480 operation. This allows for remote operation of the GNS 480 if desired for a specific
installation.
1.2.2.6 RS232 Interfaces
The GNS 480 has seven external, user-configurable RS232 serial ports (five are bi-directional, and two
are receive-only). The serial ports can be configured to receive RS232 serial data from various sources,
including another GNS 480, an SL30, an SL70/SL70R, an MX20, a FADC, an Altitude Encoder, a GTX
33/330 transponder, a GTX 32/327 transponder and a CO Guardian (COG) carbon monoxide sensor.
These ports can also be configured to transmit RS232 serial data in various formats, including
MAPCOM. These outputs allow the GNS 480 to transmit data to the MX20, SL30, SL70/SL70R, GTX
33/330 and GTX 32/327. In addition, the GNS 480 can transmit data to any unit that accepts the standard
Garmin AT MAPCOM data.
1.2.2.7 RS422 Interfaces
The GNS 480 has one user-configurable, bi-directional RS422 port. This port is not currently used.
1.2.2.8 ARINC 429 Interfaces
The GNS 480 has three ARINC 429 input ports and two ARINC 429 output ports. Each port is user-
configurable for low or high speed operation. The GNS 480 can be set up to receive air data, heading
data, wind data or traffic data from suitable equipment. The outputs can be set up to output ARINC 429
data in various formats.
1.2.2.9 Baro Correction Input
The GNS 480 has one interface that allows a baro correction potentiometer to be connected directly to
the GNS 480. This input can be calibrated at installation, allowing a wide variety of altimeters to be
connected to the GNS 480.
1.2.2.10 Synchro Input
The GNS 480 has one XYZ synchro input that allows synchro heading to be supplied to the GNS 480.
1.2.2.11 Message Audio Output
The GNS 480 has one 500 Ωaudio output that can be connected to an audio panel to provide audible
messages to the pilot. This output can be automatically inhibited by other equipment if required.
1.2.2.12 Infrared Interface
The GNS 480 has one user-configurable bi-directional infrared port. This port is not currently used but
in the future will be used to send and receive flight plan and user waypoint information through a PDA
that has infrared capabilities.

General Information
1-6 560-0982-01 Rev A GNS 480 (CNX80) Installation Manual
1.3 SPECIFICATIONS
This section includes detailed electrical, physical, environmental and performance specifications for the
GNS 480.
1.3.1 ELECTRICAL
Input voltage.................................................. 10 VDC to 36 VDC
Input current (Main input – P1) .................... 1.4 A typical, 2.2 A max (heater off) at 14 VDC
2.4 A typical, 3.2 A max (heater on) at 14 VDC
700 mA typical, 1.1 A max (heater off) at 28 VDC
1.2 A typical, 1.6 A max (heater on) at 28 VDC
Note: backlight heater element turns on when
internal temperature is below approx. 42°C
Input current (VHF Nav input – P7) ............. 450 mA typical, 700 mA max at 14 VDC
200 mA typical, 350 mA max at 28 VDC
Input current (Comm input – P4) .................. 270 mA typical, 350 mA max at 14 VDC, receive
130 mA typical, 175 mA max at 28 VDC, receive
2.1 A typical, 3.2 A max at 14 VDC, transmit
1.0 A typical, 1.6 A max at 28 VDC, transmit
Note: receive max at full receive audio, transmit
max at 90% modulation at 1000 Hz.
Internal fuses ................................................. Main input: 3 amp fast-blow, socketed on board (2)
Nav input: 3 amp fast-blow, socketed on board
Comm input : 7 amp fast-blow, soldered in board
Memory backup ............................................ Internal flash memory
1.3.2 PHYSICAL
Height............................................................ 3.3 inches (84 mm)
Width............................................................. 6.25 inches (159 mm)
Depth............................................................. 11.7 inches (297 mm) (behind panel, including
mounting frame and connectors)
Weight........................................................... 5.8 lbs. (2.6 kg) unit only
0.7 lbs. (0.3 kg) mounting tube
1.3.3 ENVIRONMENTAL
The GNS 480 unit is designed and tested to meet appropriate categories as shown in the Environmental
Qualification Form included in Appendix A.
Operating temperature................................... -20°C to +55°C
Storage temperature ...................................... -55°C to +85°C
Temperature variation................................... 2°C per minute
Humidity .......................................................95% at 50°C
Maximum continuous altitude ......................35,000 feet

General Information
GNS 480 (CNX80) Installation Manual560-0982-01 Rev A 1-7
Decompression ..............................................55,000 feet (operation for up to 30 minutes at
55,000 feet supported)
Cooling ..........................................................Not required
1.3.4 DISPLAY
TSO/JTSO Compliance .................................TSO-C113 (SAE/AS8034)/JTSO-C113
Active Display Size .......................................3.8” Diagonal (3.1” (W) x 2.1”(H))
Display Format ..............................................320 pixels (W) x 240 pixels (H)
Viewing Angle (with 5:1 contrast ratio min.)
Left/Right..........................................60°from perpendicular
Up .....................................................60°from perpendicular
Down ................................................35°from perpendicular
Brightness
Maximum..........................................130 fL
Minimum ..........................................0.2 fL (at zero ambient light)
* Minimum brightness can be adjusted by the user to a value > 0.2 fL
1.3.5 GPS/WAAS RECEIVER PERFORMANCE
TSO/JTSO Compliance .................................TSO-C146a (RTCA/DO-229C)/JTSO-C146
Number of channels.......................................15 (12 GPS and 3 GPS/WAAS/SBAS)
Frequency ......................................................1575.42 MHz L1, C/A code
Sensitivity (acquisition).................................-116 dBm to -134.5 dBm GPS
-116 dBm to -135.5 dBm WAAS
Sensitivity (drop lock) ...................................-144 dBm
Dynamic range...............................................> 20 dB
Lat/Long position accuracy ...........................<1 meter RMS typical with WAAS
(horizontal/vertical)
Velocity .........................................................1000 knots maximum (above 60,000 ft)
TTFF (time to first fix)..................................1:45 min. typical with current almanac, position, and
time
Reacquisition .................................................10 seconds typical
Position update interval .................................0.2 sec (5 Hz)
1 pps (pulse per second) ................................±275 nsec of UTC second
Datum ............................................................WGS-84
SATCOM compatibility ................................Compatible on aircraft equipped with SATCOM
Antenna power supply ...................................35 mA typical, 40 mA max at 4.7 VDC

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1-8 560-0982-01 Rev A GNS 480 (CNX80) Installation Manual
1.3.6 COMM RECEIVER PERFORMANCE
TSO/JTSO Compliance................................. TSO-C38d (RTCA/DO-186, DO-186a)/JTSO-2C38e
Class .............................................................. D
Frequency range............................................ 118.000 to 136.975 MHz, 760 channels
Sensitivity...................................................... 1µV (2µV hard) for 6dB S+N/N with 30%
modulation at 1000Hz
Selectivity...................................................... < 6dB variation at ±7 kHz, > 60dB at ±22 kHz
Speaker audio output level............................ 12 watts into 4Ω, 8 watts into 8Ω
Headphone audio output level....................... 280 mW into 100Ω, 120mW into 500Ω
Distortion ...................................................... < 5% at rated output at 1000 Hz
AGC characteristics ...................................... < 3 dB variation in audio output from 5µV to
100mV input, 15% to 90% modulation
Squelch control ............................................. Automatic squelch with manual override
1.3.7 COMM TRANSMITTER PERFORMANCE
TSO/JTSO Compliance................................. TSO-C37d (RTCA/DO-186, DO-186a)/JTSO-2C37e,
TSO-C128 (RTCA/DO-207)/JTSO-2C128
Class .............................................................. 4
Output power................................................. 8 watts minimum carrier at >12 VDC input,
6 watts minimum at 10 VDC input (transmit is
locked out below 9 volts input)
Frequency range............................................ 118.000 to 136.975 MHz, 760 channels
Frequency tolerance ...................................... ±15 ppm from -20°C to +70°C
Microphone input.......................................... Two inputs, standard carbon or dynamic mic with
integrated preamp providing minimum 70mV rms
into 1000Ωload
Modulation capability ................................... 85% with 100mV to 1000mV rms microphone input
at 1000 Hz
Audio frequency distortion ........................... < 10% at 85% modulation at 350 to 2500 Hz
Audio frequency response............................. < 4 dB variation with 350 to 2500 Hz, 85%
modulation
Carrier noise level ......................................... > 35 dB down
Sidetone output ............................................. up to 280 mW into 100Ω, 120 mW into 500Ω
Duty cycle: .................................................... 100%
Stuck mic time-out ........................................ 35 second time-out, reverts to receive

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GNS 480 (CNX80) Installation Manual560-0982-01 Rev A 1-9
1.3.8 NAV RECEIVER PERFORMANCE
1.3.8.1 VOR
TSO/JTSO compliance..................................TSO-C40c (RTCA/DO-196)/JTSO-2C40
Operational class ...........................................N/A
Accuracy category .........................................B {-46oC to + 55o C }
Frequency range.............................................108.00 to 117.95 MHz in 50 kHz increments
Frequency tolerance.......................................0.0008%
Cross modulation products ............................At least 60 dB down
Receiver sensitivity........................................108 MHz –115 dBm typical
117 MHz –117 dBm typical
Course accuracy.............................................RTCA DO-196 two sigma limit: 3o
GNS 480 performance: less than 0.5otypical
Audio output..................................................With a 1 kHz tone 30% modulation at least 100 mW
output into 500 Ωloads
Ident/voice .....................................................With 100 mV input, 30% modulation at 1020 Hz,
the ident/voice tone ratio shall not be less than15 dB
Audio response ..............................................Less than 6 dB variation from 350 Hz to 2500 Hz
1.3.8.2 Localizer
TSO/JTSO compliance..................................TSO-C36e (RTCA/DO-195)/JTSO-C36e
Operational class ...........................................A {manual landing systems}
Accuracy category .........................................B {-46oC to + 55oC }
Frequency range.............................................108.00 to 111.95 MHz
Frequency tolerance.......................................0.0008%
Cross modulation products ............................At least 60 dB down
Receiver sensitivity........................................-115 dBm typical
Centering error...............................................RTCA DO-195 two sigma limit: 6.6% of full scale
GNS 480 performance: less than 1.0% typical (1.5 mV)
Audio output..................................................With a 1 kHz tone 30% modulation at least 100 mW
output into 500 Ωloads
Ident/voice .....................................................With 100 mV input, 30% modulation at 1020 Hz,
the ident/voice tone ratio shall not be less than15 dB
Audio response ..............................................Less than 6 dB variation from 350 Hz to 2500 Hz
1.3.8.3 Glideslope
TSO/JTSO compliance..................................TSO-C34e (RTCA/DO-192)/JTSO-C34e
Operational class ...........................................N/A
Accuracy category .........................................B {-46oC to + 55oC }

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1-10 560-0982-01 Rev A GNS 480 (CNX80) Installation Manual
Frequency range............................................ 329.150 to 335.00 MHz
Frequency tolerance ...................................... 0.0008%
Cross modulation products............................ At least 60 dB down
Receiver sensitivity....................................... -95 dBm typical
Centering error .............................................. RTCA DO-195 two sigma limit: 6.7% of full scale
GNS 480 performance: less than 2.0% typical (3.0 mV)
1.3.8.4 Computation Rates
The tuned active frequency is computed 10 times per second. If the VOR monitor function is activated,
20% of each second is allocated to the monitored frequency, slightly decreasing the active to frequency
computation rate. It is important to note that the monitored frequency is only updated once per second.
1.3.9 AVIONICS INTERFACES
1.3.9.1 Main CDI (GPS or VHF Nav)
1.3.9.1.1 Deviations / Flags / Annunciators
CDI L/R deviation......................................... ±150 mv full scale (200 Ωload max)
TO/OFF/FROM flag ..................................... ±250 mv, TO/FROM (200 Ωload max)
Nav valid flag................................................ +300 mv for valid indication (200 Ωload max)
Nav superflag ................................................ Vin - 2 volts (minimum) for valid, source capability
of 400 mA
VDI up/down................................................. ±150 mv full scale (200 Ωload max)
VDI valid flag ...............................................+300 mv for valid indication (200 Ωload max)
VDI superflag................................................ Vin - 2 volts (minimum) for valid, source capability
of 400 mA
GPS/Nav Annunciators ................................. Open collector outputs capable of sinking up to 400
mA for turning ON annunciator lamps
1.3.9.1.2 OBS Resolver
TSO/JTSO compliance ................................. TSO-C40c (DO-196)/JTSO-2C40
Applicable documents................................... RTCA DO-196
Operational class........................................... N/A
Accuracy category......................................... B {-46oC to + 55oC}
Output signal................................................. 300 Hz ±2 Hz (rounded square wave)
Output voltage (automatically
adjusted during calibration) .......................... 5 Vpp to 10 Vpp
Input voltage max (calibrated) ...................... 5 Vpp (when OBS is set to maximum)
Resolver voltage gain (loss).......................... 1:1 maximum, 2:1 minimum
Output loading at max voltage ...................... 100 ohms impedance
Accuracy/Resolution..................................... 0.25orounded to 1osteps