Sagetech MXS User manual

© Sagetech Avionics 2022 Proprietary Confidential
MXS System Description and Installation Manual
UM06945
February 2022

MXS System Description and Installation Manual UM06945
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Contents
1.0 Introduction ......................................................................................................................... 6
1.1 Sagetech Customer Support ............................................................................................ 6
1.2 Equipment Safety and Precautions.................................................................................. 6
1.2.1 RF Port Termination Warning................................................................................... 6
1.2.2 Electromagnetic Exposure Statements and Warnings ............................................. 6
2.0 System Information ............................................................................................................. 8
2.1 Specifications.................................................................................................................... 8
2.2 TSO Authorizations........................................................................................................... 9
2.3 TSO Deviations and Incomplete..................................................................................... 10
2.4 FCC ID ............................................................................................................................. 10
2.5 Device Marking............................................................................................................... 11
2.6 Continued airworthiness................................................................................................ 11
2.7 Installation Approvals and System Limitations.............................................................. 11
2.8 Regulatory Compliance .................................................................................................. 12
2.9 Environmental Specifications......................................................................................... 13
3.0 System Overview ............................................................................................................... 14
3.1 System Description......................................................................................................... 14
3.2 System Functionality...................................................................................................... 15
3.2.1 Transponder............................................................................................................ 15
3.2.2 ADS-B In .................................................................................................................. 15
3.2.3 ADS-B Out................................................................................................................ 16
3.2.4 Altitude Encoder ..................................................................................................... 16
3.2.5 Attributes of the MXS transponder include the following ..................................... 16
3.2.6 Control Interface..................................................................................................... 17
4.0 Installation ......................................................................................................................... 17
4.1 Mounting the MXS ......................................................................................................... 18
4.2 Connecting the GPS Interface ........................................................................................ 19
4.3 Connecting the RF Antennas.......................................................................................... 20
4.4 Routing and Connecting the Antenna Cable.................................................................. 22
4.5 Connecting the Altitude Sensor/Encoder to the System Static Pressure ...................... 22
4.6 Cooling Requirements.................................................................................................... 23
5.0 Mechanical Characteristics................................................................................................ 25
5.1 Dimension, Weight & Material ...................................................................................... 25
5.2 Mechanical Connection.................................................................................................. 25
5.2.1 MXS Main Connector .............................................................................................. 26

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6.0 Electrical Characteristics.................................................................................................... 27
6.1 Main Connector.............................................................................................................. 27
7.0 Power up Process............................................................................................................... 32
7.1 Setup Equipment............................................................................................................ 32
7.2 Power Up The MXS......................................................................................................... 32
7.3 Check For the Boot Loader Message.............................................................................. 33
7.4 Send Installation Message.............................................................................................. 33
7.5 Send GPS Information .................................................................................................... 37
7.6 Send Operating message................................................................................................ 39
7.7 Send Flight ID.................................................................................................................. 42
7.8 ADS-B In.......................................................................................................................... 43
7.9 Monitor Health and Status............................................................................................. 44
7.10 Health Monitoring and Built-in-Test (BIT)...................................................................... 45
7.11 System Health and Status Overview .............................................................................. 45
7.12 Status Response Messages ............................................................................................ 46
8.0 Revision History ................................................................................................................. 52
9.0 Appendix A –Shielded Cable Assembly Construction........................................................ 53

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Figures
Figure 3-1 Diagram of MXS Maximum Mode C/Mode S Installation..........................................................14
Figure 3-2 System Block Diagram of MXS Minimum Mode C/Mode S Installation....................................15
Figure 4-1 Diagram and Identification of MXS Connectors and Mounting Holes Mounting the MXS .......18
Figure 4-2 Connectors to Top and Bottom Antenna...................................................................................20
Figure 4-3 Pressure Altitude Encoder Port to Static Pressure ....................................................................23
Figure 4-4 Cooling Methods vs. Device Temperature ................................................................................24
Figure 5-1 MXS Dimensions ........................................................................................................................25
Figure 5-2 Mechanical Connections............................................................................................................26
Figure 5-3 MXS Main Connector (Female) Pin Locations............................................................................26
Figure 5-4 Transponder Main Connector - Front View...............................................................................27
Figure 7-1 MXS Com Test GUI.....................................................................................................................32
Figure 7-2 Boot Loader Message ................................................................................................................33
Figure 7-3 Installation Message..................................................................................................................37
Figure 7-4: GPS Message.............................................................................................................................38
Figure 7-5 Operating Message....................................................................................................................41

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Tables
Table 2-1 List of Environmental Operating Conditions...............................................................................13
Table 3-1 Control Interface.........................................................................................................................17
Table 4-1 Installation Sections....................................................................................................................17
Table 4-2 List of Common Mounting Parts and Vendors............................................................................19
Table 4-3 List of Common Mounting Parts and Vendors............................................................................20
Table 4-4 MXS Antenna Requirements.......................................................................................................21
Table 4-5 Example Antennas ......................................................................................................................22
Table 4-6 Antenna Cable Connector Parts..................................................................................................22
Table 5-1 Mechanical Attributes.................................................................................................................25
Table 6-1 Pin-Out Definition .......................................................................................................................28
Table 6-2 Communication Port Options .....................................................................................................30
Table 7-1 Aircraft Size .................................................................................................................................33
Table 7-2 Emitter Categories ......................................................................................................................34
Table 7-3 Max Airspeed ..............................................................................................................................34
Table 7-4 Baud Rate Options ......................................................................................................................35
Table 7-5 SIL/SDA settings ..........................................................................................................................35
Table 7-6 SQUAWK Code Logic ...................................................................................................................40

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1.0 Introduction
This manual provides information intended for use by persons who, in accordance with current regulatory
requirements, are qualified to install this equipment. Installation requirements may vary, depending on
the specifics of each aircraft, and this manual is intended as a guideline for that purpose. This manual
assumes familiarity with the setup and operation of the aircraft systems that interface with the MXS.
1.1 Sagetech Customer Support
Sagetech Avionics is dedicated to making integration of our MXS a straight-forward and simple exercise.
We want your experience with Sagetech to be unparalleled in product quality and customer service. If you
have questions, contact Sagetech Avionics customer support at:
[e-mail]
We also are interested in your feedback on our products, documents, and customer service.
1.2 Equipment Safety and Precautions
This product uses semiconductors that can be damaged by electrostatic discharge (ESD). When handling,
use standard ESD practices to ensure the MXS is not damaged.
1.2.1 RF Port Termination Warning
Important:
Whenever power is applied to the MXS, a 50-ohm load must be connected to the
SMA connector of any unused antenna port. Use a commercially available 50-ohm
load rated for pulses of 500W with a 1% duty cycle and a maximum VSWR of 1.5:1
between 1030MHz and 1090MHz. A load with a higher VSWR may cause permanent
damage to the transponder. (Refer to Section 4.3. Connecting the RF Antennas)
1.2.2 Electromagnetic Exposure Statements and Warnings
The MXS equipment has been tested and found to comply with the limits for a Class B digital device,
pursuant to Part 87 of the FCC Rules. These limits are designed to provide reasonable protection against
harmful interference in a residential installation. This equipment generates, uses, and can radiate radio
frequency energy and, if not installed and used in accordance with the instructions, may cause harmful
interference to radio communications. However, there is no guarantee that interference will not occur in
all installations. If this equipment does cause harmful interference to audio or visional reception, which
can be determined by turning the equipment off and on, the user is encouraged to try to correct the
interference by one or more of the following measures:
•Reorient or relocate the receiving antenna.
•Increase the separation between the equipment and receiver
•Connect the equipment into a different power source than receiver.
•Consult the dealer or an experienced RF equipment installation technician for help.

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This device complies with FCC Part 87 rules. Operation is subject to the following two conditions:
•This device may not cause harmful interference.
•This device must accept any interference received, including interference that may cause
undesired operation.
Exposure Statement
This device meets the FCC requirements for RF exposure in public or uncontrolled
environments. A minimum separation of persons to the antenna of 20cm must be
observed.
FCC Warnings
Changes or modifications not approved by Sagetech could void the user’s authority
to operate the equipment.

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2.0 System Information
2.1 Specifications
Part Number
10-0000
Certification
USA (FAA): TSO-C112e, TSO-C166b, TSO-C88b
*See Section 2.2 for specific TSO information
Advisory Circulars
AC20-165B, AC43-6D, AC20-172B, AC20-115C, AC20-152
RTCA Compliance
Environmental: DO-160G (see Environmental Specifications, section 2.9)
Software Category: DO-178C Design Assurance Level C
Hardware Category: DO-254, Design Assurance Level C
Other: DO-181E, DO-260B, AS8003, ARINC 718
Compliance
ATC Transponder Functionality: 14 CFR 91.215, 91.217, 91.413
ADS-B out functionality: 14 CFR 91.225, 91.227
Export Compliance
ECCN 7A994
Size
Width: 2.52in [64.0mm], Height: 1.00in [25.4mm], Depth: 3.50in [89.0mm]
Weight
<7oz
Chassis Ground
The unit is not required to have a chassis ground. The external chassis is non-
conductive
Power Requirements
28VDC 7.5 Watts nominal (20W maximum)
14VDC 7.5 Watts nominal (20W maximum)
Inrush Current <6A
Normal Operation range: 14-28VDC
Minimum and Maximum operating range: 10-32VDC
Electrical Connectors
2x Female SMA Connectors, Female 51pin Micro-D Connector
Interfaces
RS-232, RS-422, Ethernet, GND/Open Discrete Inputs, RF Suppression Bus
Operating Temperature
-40° to +70°C (-40° to +158°F)
Storage Temperature
-55° to +85°C (-67° to +185°F)
Maximum Altitude
55kft
Functionality
Mode S Transponder
1090ES ADS-B In and Out
Integrated Altitude Encoder tolerance per AS8002
Operation
Startup Time: <2 seconds to Transmission,
<20 seconds for BIT to complete and fully functionality
Built in Test: Fault monitoring detailed in SDIM (ICD02373)
ADS-B Receive -79dBm at the antenna, -82dBm at the SMA.
Sensitivity Class A2
Mode S (Class 1 Transponder) 250W - 500W
Transponder Level 2[dels]
Scheduled Maintenance
The MXS Transponder must be inspected and tested every 24 months
subject to the requirements of FAA documents 14 CFR Part 43 Appendix F.
Repairability
Repairs performed at the FAA certified Repair Station.

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2.2 TSO Authorizations
The MXS meets the following TSO’s.
TSO
NO.
Class/Type
DO-178C/
DO-254 DAL
Function
TSO Title
C112e
Class 1
Level 2[dels]
C/C
ATCRBS / Mode S
Transponder
Airborne Equipment
Air Traffic Control Radar Beacon
System/Mode Select
(ATCRBS / MODE S) Airborne
Equipment
C166b
Class A2
C/C
1090ES MHz ADS-B
and TIS-B Equipment
Extended Squitter Automatic
Dependent Surveillance -
Broadcast (ADS-B) and Traffic
Information Service -
Broadcast (TIS-B) Equipment Operating
on the Radio
Frequency of 1090 Megahertz (MHz)
C88b
N/A
C/C
Altitude Encoder
Automatic Pressure Altitude Reporting
Code-Generating Equipment

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2.3 TSO Deviations and Incomplete
TSO
Deviation
C112e
Sagetech was granted a deviation from TSO-C112e Paragraphs 3.e and 6.f to use
RTCA/DO-178C in place of RTCA/DO-178B.
C112e
Sagetech was granted a deviation from RTCA DO181E §2.2.19.1.12.4 to not implement
Air-Initiated Comm-B support. Air-initiated Comm-B messages are neither processed nor
transmitted.
C112e
Sagetech was granted a deviation from RTCA DO-181E §2.2.19.2.3.1 to not implement
multi-site message support, as it applies to the Comm-B operation of Level 2 transponders.
C112e
Sagetech was granted a deviation from RTCA DO-181E §2.2.19.2.3.2: Multisite Directed
Comm-B Transmissions requirement is N/A due to not implementing Air-Initiated Comm-
B support and multi-site message support
C112e
Sagetech was granted a deviation from RTCA DO-181E §2.2.19.2.3.3: Multisite Comm-B
Closeout requirement is N/A due to not implementing Air-Initiated Comm-B support and
multi-site message support.
C112e
Sagetech was granted a deviation from RTCA DO-181E §2.2.19.2.3.4: Automatic Comm-B
Closeout requirement is N/A due to not implementing Air-Initiated Comm-B support and
multisite message support
C112e
Sagetech was granted a deviation from RTCA DO-181E §2.2.19.2.3.5: Significance of PC
Command requirement is N/A due to not implementing Air-Initiated Comm-B support and
multisite message support
C166b
Sagetech was granted a deviation from TSO-C166b Paragraphs 3.e and 6.h to use
RTCA/DO-178C in place of RTCA/DO-178B.
C88b
Sagetech was granted a deviation from TSO-C88b Paragraphs 3.e and 6.h to use RTCA/DO-
178C in place of RTCA/DO-178B.
C88b
Sagetech was granted a deviation from TSO-C88b Paragraph 3.d to use RTCA/DO-160G in
place of RTCA/DO-160E.
2.4 FCC ID
Model
FCC ID
MXS 10-0000
YT5MX

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2.5 Device Marking
The Part number 10-0000 includes the released hardware and software configuration.
2.6 Continued airworthiness
Every 24 Calendar months the MXS must be checked for Transponder and Altitude Encoder performance.
The Transponder must be tested, inspected and found to comply with 14 CFR Part 91.413 as described in
14 CFR 43 Appendix F. The altitude Encoder must be tested to ensure correspondence to the primary flight
altimeter, as described in AC 43-6D and 14 CFR 43 Appendix E in order to meet the maintenance
requirements of 14 CFR Part 91.411. If the difference between the automatic reporting output and the
altitude displayed at the altimeter shall not exceed 125 feet.
2.7 Installation Approvals and System Limitations
1. This article meets the minimum performance and quality control standards required by the
applicable technical standard orders (TSOs). Those installing this article, on or in a specific type or
class of aircraft, must determine that the aircraft installation conditions are within the applicable
TSOs standards. TSO articles must have separate approval for installation in an aircraft. The article
may be installed only according to 14 CFR parts 43 or the applicable airworthiness requirements.
2. All antennas used in the installation must meet the requirements specified in this manual.
3. The GPS receiver must use antenna meeting the requirements specified in this manual.
4. It is the installer’s responsibility to ensure the ADS-B Out system is compliant with AC 20-165A,
14 CFR 91.225 (b) and 91.227 when installed in accordance with Sagetech’s installation
instructions.
5. The MXS Transponder may be optionally configured to support single or diversity antenna
installations.

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Note: If the MXS is configured for single antenna installations, a 50-ohm termination is required
on the Top antenna port.
2.8 Regulatory Compliance
Aircraft using Sagetech’s MXS Transponder need to evaluate their need to be compliant with 14 CFR
91.215, 91.225, and 91.227. While in airspace with transponder equipage requirements specified in 14
CFR 91.215, MXS must be maintained to 14 CFR Part 91.413. While in ADS-B out airspace specified 14 CFR
Part 91.225, MXS must be configured to meet requirements of 14 CFR 91.225 and 91.227.
For MXS to be compliant with the ADS-B out requirements of 14 CFR 91.225 and 91.227, a compliant
position source must be used. See section 4.2 for more information.
To meet 14 CFR 91.225 and 91.227 with no limitations, active in-flight control is necessary. The Sagetech
provided User Interface GUI can be used or the flight computer can be programed to communicate with
the MXS via the Sagetech protocol defined in ICD02373. Section 7 details the power up and configuration
process using the Sagetech provided MX Com Test GUI.
Additional Guidance for ADS-B out installations and approvals can be found in AC-20-165B and for ADS-B
in applications reference AC 20-172B.

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2.9 Environmental Specifications
The MXS was designed and verified to perform its intended function while operating in the environments
listed in Table 2-1.
Table 2-1 List of Environmental Operating Conditions
Environment
DO-160G
Section
Category
Temperature and Altitude
Operating Low Temp
Operating High Temp
Short-Time Operating Low Temp
Short-Time Operating High Temp
Loss of Cooling
Ground Survival Low Temp
Ground Survival High Temp
Altitude
Decompression Test
Overpressure Test
4
B4F1
-40 °C
+70 °C
-40 °C
+70 °C
N/A
-55 °C
85 °C
55,000 Feet
N/A
N/A
Temperature Variation
5
S1(1)
Humidity
6
B
Operational Shocks & Crash Safety
7
B
Vibration
8
S (Zone 1; Curve C)
U (Zone 1; Curve G)
Explosion Proofness
9
E
Magnetic Effect
15
Y
Power Input
16
BXI(2)
Voltage Spike
17
B
Audio Frequency Conducted Susceptibility –Power Inputs
18
B
Induced Signal Susceptibility
19
ACX
Radio Frequency Susceptibility (Radiated and Conducted)
20
TT
Emission of Radio Frequency Energy
21
BB
Lightning Induced Transient Susceptibility
22
B2K3L3
*B2K1L1 for power lines
Electrostatic Discharge
25
A
Note: The Altitude Encoder is only calibrated to go up to 55kft. It can be calibrated to 85kft upon request.

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3.0 System Overview
The MXS provides transponder functions within the Secondary Surveillance Radar (SSR) system. The SSR
system provides situation awareness to Air Traffic Control (ATC) and the remote pilot.
3.1 System Description
An installed MXS interfaces to a Host (typically a Flight Computer or Autopilot)
1
, GPS Sensor, Barometric
Pressure Source, and Aircraft Control Signals.
Figure 3-1 is a block diagram depiction of the maximum integration of MXS. A minimum Mode C/Mode S
installation is shown in Figure 3-2.
1
In this document, the messaging protocol used to communicate between the MXS, and the host (typically a Flight
Computer or Autopilot) will be referred to as the “Host Interface”.See Section Error! Reference source not found. and
Table 6-2 for more information about the serial and Ethernet data protocol used for the Host Interface, and the pins used
for serial communications on the Main Connector. See Section ICD02373 for definitions of the message types comprising
the Host Interface.

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Figure 3-1 Diagram of MXS Maximum Mode C/Mode S Installation

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Host Autopilot/
Control Head
MXS
Pressure
Port
TB
50 Ohm
Terminator
Main Connector
Power Supply
10 - 32 VDC
RS-232/422Port
Host Interface
Figure 3-2 System Block Diagram of MXS Minimum Mode C/Mode S Installation
3.2 System Functionality
The MXS transponder performs the following basic functions:
3.2.1 Transponder
•Verified to meet the applicable requirements of DO-181E for a Mode S Class 1, Level 2
transponder.
•Interacts with air traffic control (ATC) by transmitting and receiving standard secondary
surveillance radar pulses per ICAO requirements. The transponder replies to ATCRBS
interrogations with a squawk code and pressure altitude data.
•Provides Mode S replies (includes data such as ICAO address and call sign) and is capable of being
selectively interrogated.
3.2.2 ADS-B In
•Verified to meet the applicable requirements of DO-260B for a Class A2 ADS-B Receiver.
•The MXS receives Automatic Dependent Surveillance-Broadcast In (ADS-B), Extended Squitter (ES)
messages that have been transmitted automatically from surrounding planes and the Air Traffic
Control (ATC) system.
•ES messages report Position, Velocity, Identification and Category, Target State and Status, and
Aircraft Operational Status. From this data, MXS generates ADS-B, TIS-B and ADS-R reports for
delivery to the flight computer which communicates the data to the user.

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•Transponders with ADS-B In are useful for sense and avoid applications by providing the user with
surrounding traffic information with a nominal range of 120 nautical miles (NM).
3.2.3 ADS-B Out
•Verified to meet the applicable requirements of DO-260B for a Class A2 ADS-B Transmitter.
•Provides Flight computer-controlled Automatic Dependent Surveillance-Broadcast Out (ADS-B)
capability.
•Transmits Extended Squitter (ES) and Acquisition Squitter messages at regular intervals, providing
Position, Velocity, Identification and Category, Emergency/Priority Status, Target State and Status,
Aircraft Operational Status, and other aircraft data. There is no way to disable Acquisition squitter
independently of the Mode S functionality
•Altitude data for the ES can be based on the MXS’s integrated altitude encoder, or one provided
external to the MXS.
•GPS data, also included in the ES, is provided to the MXS from an external source.
3.2.4 Altitude Encoder
•Verified to meet the applicable requirements of AS8003 for a Pressure Altitude Encoder.
•Computes own-ship barometric altitude with an integral pressure sensor and encoder.
•Calibrated up to 55,000ft. Can be calibrated up to 85,000ft upon request.
3.2.5 Attributes of the MXS transponder include the following
•GPS input is accepted from the Host Interface command link, or from NMEA or Accord GPS sensors
over serial communication ports.
•Supports antenna diversity (dual antennas located on the top and bottom of the aircraft).
•Supports aircraft system installations of one or two Transponder/ADS-B L-Band antennas
•Integrated pressure altitude sensor and encoder that provides required altitude data when the
static pressure port is connected to a static air pressure line.
•The MXS measures approximately 3.50in (89.0mm) x 2.09in (53.0mm) x 1.00in (25.4mm). (see
Section 5.1)
•Operating temperature is -40°C to +70°C
2
•Storage temperature is -55°C to +85°C.
•Nominal input supply voltage range is 14-28 VDC.
•Aircraft Flight computer communication is either RS-422, RS-232 or Ethernet using the Host
Interface protocol defined ICD02373
3.2.6 Control Interface
The MXS has a control and configuration serial interface that is used to configure the equipment at
installation time as well as command and control the device during operation. Typically, the MXS is
2
Refer to Section 4.6 Cooling Requirements.

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connected to an autopilot or flight computer on an unmanned aircraft or a control interface on a manned
aircraft.
At the time of installation, the control interface allows the user to input specific information about the
aircraft that is used in Mode S and ADS-B messages. The interface also allows the user to configure the
Baud rate of Com0 and Com1, set the IP address (which will be used for ethernet communication)
configure the weight on wheels “method”and select Single or Diversity Antenna installation. This data
will be saved in nonvolatile memory and loaded on every power up.
While operating the MXS the serial interface allows the user to change the operating mode, enable Ident,
change emergency status, and get critical system and transponder health information.
To comply with 14 CFR 91.225 with no operating limitations, dynamic control is required.
The MXS Serial interface is defined in ICD02373.
Table 3-1 Control Interface
Communication Interface
Specifications
Ethernet
IEEE 802.3 10Base-T
RS-232
Configurable bps (8N1) Com0 or Com1
RS-422
Configurable bps (8N1) Com0 or Com1
RS-485
Half Duplex Interface by connecting 422 Rx and Tx
lines R+ with T+ and R- with T-
Configurable bps (8N1) Com0 or Com1, MXS does
not have logic to avoid packet collision; Host
interface must manage packet transmit and
receive timing.
4.0 Installation
This section explains the installation of the MXS unit and its connections. Table 4-1 lists the sections
documenting MXS installation.
Table 4-1 Installation Sections
Installation
Step
Description
4.1
Mounting the MX
4.2
Connecting the GPS Interface
4.3
Connecting the RF Antennas
4.4
Routing and Connecting the Antenna Cable
4.5
Connecting the Altitude Sensor/Encoder to the System Static Pressure
4.6
Cooling Requirements
MXS requires the following additional equipment:

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•GPS Receiver
•Transponder Antenna
•Control Interface with Annunciation
Figure 4-1 shows a labeled diagram of MXS’s connectors and mounting holes, which should be used as a
reference during the installation process.
Note: The Main Connector and its connection to the MXS are described in Section 5.2 Mechanical
Connection and Section 6.0 Electrical Characteristics.
Figure 4-1 Diagram and Identification of MXS Connectors and Mounting Holes Mounting the MXS
4.1 Mounting the MXS
•The MXS needs to be mounted in a location protected from weather.
•MXS should be mounted away from sources of excess heat to better guarantee an operating
environment within its designed temperature range. Mount on a heat sink, if necessary, to
maintain device junction temperature below 85°C. With adequate airflow and lower ambient
operating temperatures, the MXS can be mounted directly to the airframe.
•Refer to Section 5.1 Dimension, Weight & Material for mounting dimensions.
•Sagetech recommends applying Loctite 242 Thread locker to the machine screw threads or using
locking washers or locking nuts.
•The hardware listed in Table 4-2 are potential candidates for use in custom installation.

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Table 4-2 List of Common Mounting Parts and Vendors
Description
Vendor
Vendor PN
Quantity
Machine Screw, Round Head, PH1, .112(#4)-40
Thread Size, 1", Zn Plated Steel
McMaster-
Carr
90279A115
2
Machine Screw, Round Head, PH1, .112(#4)-40
Thread Size, 1-1/4", Zn Plated Steel
McMaster-
Carr
90279A117
2
Flat Washers, Black-Oxide Steel Oversized
Washer for Number 4 Screw Size, 0.125" ID,
0.25" OD
McMaster-
Carr
98029A024
8
Locknut, low-Strength Steel Nylon-Insert, Zinc-
Plated, 4-40 Thread Size
McMaster-
Carr
90631A005
4
4.2 Connecting the GPS Interface
GPS data must be provided to the MXS from the aircraft system in one of three ways:
1. NMEA data sent via RS232/RS422 to COM0 or COM1. MXS accepts GGA, GLL, RMC and VTG NMEA
sentences. If NMEA Protocol is used, then SIL and SDA are set to 0 automatically.
2. The proprietary Accord Binary data sent via RS232/422 to COM0 or COM1(a TSO-C145c compliant
solution). MXS accepts: The Navigation Packet, the Auxiliary Navigation Packet, and the Status
Packet. If Accord protocol is used the SIL is set to 3 and the SDA is set to 2 automatically.
3. Sagetech defined GPS message protocol as defined in ICD02373 and can be sent to COM0, COM1, or
ethernet. If the Sagetech navigation message is used, then the SIL and SDA is set by the install
message.
Per AC 20-165A an appropriate position source must be used. The total latency measured from the time
when the position is measured to when the position is transmitted must be less than or equal to 2.0
seconds. The MXS will reflect the updated position information within 100milliseconds from receiving
the position message.
The NexNav Mini LRU PN:21001 meets the requirements per AC 20-165A as it holds a TSO-C145. The
MXS is compatible with the Accord Binary protocol that the 21001 outputs.
For other TSO’d GPS receivers that use an alternative protocol the data must be translated to either the
Accord Binary format or Sagetech Defined format.
The MXS will not function correctly if multiple sources of position information are sent into the device.
User must send one source at a time.
Note: See 6.1 Main Connector for more information about the serial data protocol and the pins used for
serial communications on the Main Connector.