RTCA DO 181 : E2011

Foreword
1.0 Purpose and scope
1.1 Introduction
1.2 System overview
1.2.1 The function of mode S
1.2.2 Major operating characteristics
1.2.3 System performance
1.2.4 Basic system protocol
1.2.5 Mode S message content
1.3 Operational goals
1.4 Operational applications
1.4.1 The ATCRBS environment
1.4.2 The mode S environment
1.4.3 Mode S transponder capability levels
1.4.4 Use of the mode S data link
1.4.5 Airborne equipment
1.5 Assumptions
1.6 Test procedures
1.6.1 Environmental tests
1.6.2 Detailed test procedures
1.6.3 Installed system tests
1.7 Definitions of terms
2.0 Mode S transponder equipment performance
        requirements and test procedures
2.1 General requirements for all equipment
2.1.1 Airworthiness
2.1.2 General performance
2.1.3 Federal communications commission rules
2.1.4 Fire protection
2.1.5 Operation of controls
2.1.6 Accessibility of controls
2.1.7 Flight crew control functions
2.1.8 Optional crew control functions
2.1.9 Effects of tests
2.1.10 Equipment configuration
2.1.11 Interrogation signals
2.2 Minimum performance standards - standard
        conditions and signals
2.2.1 Definition of standard conditions
2.2.2 Receiver characteristics
2.2.3 Transmitter characteristics
2.2.4 Reply pulse characteristics
2.2.5 Side lobe suppression characteristics
2.2.6 Pulse decoder characteristics
2.2.7 Desensitization and recovery characteristics
2.2.8 Response in the presence of interference
2.2.9 Undesired replies
2.2.10 Self test and monitor(s)
2.2.11 Response to mutual suppression pulses
2.2.12 Diversity operations
2.2.13 Data handling and interfaces
2.2.14 Description of the mode S signal format
2.2.15 Mode S transponders
2.2.16 The basic transponder
2.2.17 Data link transponder description
2.2.18 Antenna
2.2.19 Power interruption
2.2.20 TCAS-compatible mode S transponder
2.3 Equipment performance - environmental conditions
2.3.1 Environmental test conditions
2.3.2 Detailed environmental test procedures
2.4 Equipment test procedures
2.4.1 Definitions of terms and conditions of test
2.4.2 Detailed test procedures
2.5 Test procedures for the surveillance and
        communications protocols
2.5.1 Introduction
2.5.2 Required test equipment
2.5.3 Selection and use of the test procedures
2.5.4 Test procedures
3.0 Installed equipment performance
3.1 Equipment installation
3.1.1 Equipment accessibility
3.1.2 Inadvertent turn off
3.1.3 Displays
3.1.4 Aircraft power source
3.1.5 Transmission line(s)
3.1.6 Antenna location
3.1.7 Mutual suppression
3.2 Conditions of test
3.2.1 Power input
3.2.2 Interference effects
3.2.3 Environment
3.2.4 Adjustment of equipment
3.2.5 Warm-up period
3.2.6 Radiation pattern
3.3 Test procedures for installed equipment
        performance
3.3.1 Conformity inspection
3.3.2 Bench tests
3.3.3 Reply frequency
3.3.4 Framing pulse spacing
3.3.5 Reply codes
3.3.6 Pressure altitude transmissions
3.3.7 Altitude reporting test
3.3.8 Reply pulse width
3.3.9 Receiver sensitivity
3.3.10 Transmitter power output
3.3.11 Received reply
3.3.12 Airspeed fixed field
3.3.13 On-the-ground condition
3.3.14 Diversity antenna installations
3.4 Flight test procedures
Membership
Tables
2.3.1.1 Environmental test groups
2.3.1.2 Performance test requirements during
         environmental tests
Figures
2.1 General pulse patterns for PAM interrogations
2.2 General pulse patterns for DPSK interrogations
2.3 Mode S reply waveform
2.4 Overview of mode S interrogation formats
2.5 Overview of mode S reply formats
2.6 Field index
2.7 The basic transponder: uplink formats
2.8 The basic transponder: downlink formats
2.9 Functional diagram of uplink coding
2.10 Functional diagram of downlink coding
2.11 The basic transponder: interrogation acceptance
2.12 All transponders: lockout initiation
2.13 All transponders: FS and VS protocol
2.14 All transponders: reply content
2.15 All data link transponders: formats
2.16 All data link transponders: interrogation
      acceptance
2.17 All data link transponders: interrogation
      coordination
2.18 All data link transponders: UM protocol
2.19 All data link transponders: B protocol
2.20 Comm-C reservation and closeout
2.21 Comm-C message handling
2.22 Comm-D reservation and closeout
2.23 Comm-D message handling
2.24 through 2.32 Test setups

Defines standards for Mode S airborne equipment (Mode S implies a combined ATCRBS/Mode S capability).