Accessory Interface
Specification
Release R32
Contents
Overview 35
1. Introduction 36
1.1 Organization 36
1.2 Applicability 37
2. Requirements 39
2.1 Developer Preview 39
2.2 Manufacturer Preview 40
3. Terminology 41
3.1 Device 41
3.2 Accessory 41
3.3 Authentication Coprocessor 41
3.4 I
2
C Bus 41
3.5 Challenge 41
3.6 Challenge Response 42
3.7 X.509 Certificate 42
3.8 Component 42
3.9 Control Surface 42
3.10 Direct User Action 43
3.11 Feature 43
3.12 USB Device Mode 43
3.13 USB Host Mode 44
3.14 Captured Cable 44
Accessories 45
4. All Accessories 46
4.1 Compliance Testing 46
4.2 Minimum Device Compatibility 46
4.3 Testing with Apple Beta Software 47
4.3.1 Beta Software Access and Installation 48
2019-09-26 | Copyright © 2019 Apple Inc. All Rights Reserved.
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4.3.2 Profiles and Logs 48
4.3.3 Issue Reporting 48
4.4 Development Tools and Emulators 49
4.5 Reference Designs & Development Kits 49
4.6 Accessory Authentication and Accessory Identification 50
4.7 Module/Component/Connector Modifications 50
4.8 Connector Assemblies 50
4.9 Adapters and Proxies 50
4.10 Mixed Headset Jack and Lightning Connectors 50
4.11 Apple USB Power Adapters 50
4.12 Apple Watch Magnetic Charging Cable 51
4.13 Apple Watch Lug 51
4.14 Device Detection 51
4.15 Multiple Simultaneous iAP2 Connections 51
4.16 Disconnecting and Reconnecting 52
4.17 Device Status Updates 52
4.18 Presentation of Device Updates 52
4.19 Relationships Between Multiple Accessories 53
4.20 iBeacon 53
4.21 Feature Duplication 53
4.22 Temperature Range 53
4.23 Integrated USB Receptacles or Lightning Receptacle (C37) 53
4.24 Integrated Non-USB Receptacles 54
4.25 User Supplied Cables and AC Power Adapters 54
4.26 Removable Storage 54
4.27 TDMA Noise 55
4.28 Attachments 55
4.29 Magnetic Interference 55
4.30 Radio Frequency (RF) Performance 56
4.30.1 Materials and Coatings 56
4.30.2 Antenna Keep-Out 56
4.30.3 Over The Air (OTA) Transmission/Reception 57
4.30.4 Specific Absorption Rate (SAR) 57
4.30.5 Near Field Communication (NFC) 57
4.31 Qi Wireless Power 58
4.32 Voice Assistants 58
4.33 Test Procedures 58
4.33.1 Device Selection 58
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Contents
5. Cases 60
5.1 Product Design 60
5.1.1 Device Protection 60
5.1.2 Integrated Lightning Connectors 61
5.1.3 Access to Inputs and Interconnects 61
5.1.4 Dock Compatibility 64
5.1.5 Qi Wireless Power and Rear Pockets 65
5.2 Acoustics 65
5.2.1 Call Quality 65
5.2.2 Speaker to Microphone Coupling 65
5.2.3 Speaker/Microphone Openings 65
5.3 Ambient Light Sensor and Proximity Sensor Interference 68
5.4 Taptic Engine 68
5.5 Magnetic Interference 68
5.6 Home Button / Touch ID Sensor 69
5.7 Camera 69
5.7.1 Geometry 69
5.7.2 Color 70
5.7.3 Surface Finish 70
5.7.4 Image Degradation Examples 70
5.8 Reliability 71
5.8.1 Device Insertion and Removal 71
5.8.2 Colorfastness 71
5.9 Environmental 71
5.10 Test Procedures 72
5.10.1 Device Models 72
5.10.2 Product Design 78
5.10.3 Taptic Engine 80
5.10.4 Home Button / Touch ID Sensor Overlays 81
5.10.5 Acoustics 82
6. Camera Attachments 84
6.1 Magnetic Interference 84
7. Covers 85
7.1 Magnetic Interference 85
7.2 Smart Covers 85
8. Screen Overlays 87
8.1 Product Design 87
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Contents
8.2 Edge Swipe and Edge Press Gestures 87
9. Cables 88
9.1 Industry Standard Connectors 88
9.2 Bundled Adapters 88
9.3 Cable Encapsulation 89
9.4 Lightning Cables 89
9.4.1 USB Receptacles 89
9.4.2 Barrel Jack Plugs 89
9.4.3 Lightning Connector Enclosure 90
9.4.4 Electromagnetic Compatibility (EMC) 91
9.4.5 Termination 92
9.4.6 Hot Bar Soldering 92
9.4.7 Encapsulation 92
9.4.8 Lightning Connector Shields 93
9.4.9 Laser Welding 97
9.4.10 Lightning to USB Charge/Sync Cables 97
9.4.11 Lightning to USB Accessory Cables 98
9.4.12 Lightning Audio Cables 100
9.4.13 Lightning to Proprietary Connector 102
9.5 Other Cables 102
9.5.1 3.5 mm Analog Audio Headset Cables 102
9.5.2 3.5 mm Headset Plug to UAC 103
9.5.3 USB-A to UAC 103
9.5.4 USB-C to UAC 103
9.6 Test Procedures 104
9.6.1 Product Design 104
9.6.2 Signal Integrity Tests 104
9.6.3 DC Resistance Tests 110
9.6.4 Cable Shield Bend Test 115
9.6.5 180° Cable Bend Test 115
10. Adapters 118
10.1 Headset Adapters (Lightning to 3.5 mm) 118
10.2 Headset Adapters (USB-A or USB-C to Lightning) 119
10.3 Headset Adapters (Integrated Lightning Receptacle (C37)) 119
10.4 Headset Adapters (3.5 mm to Lightning) 119
10.5 Ethernet Adapters (Lightning to RJ45) 120
10.6 Lightning to USB Micro-B Adapters 122
10.7 USB-C to USB Micro-B Adapters 122
2019-09-26 | Copyright © 2019 Apple Inc. All Rights Reserved.
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Contents
