Apple Watch Continuity Stack

Apple Watch Continuity Stack

iNA integrates Apple Watch (Series 4 through Series 10, Apple Watch Ultra 1 & 2, and SE) with Android by hosting on-device GATT peripheral servers and handling Apple Continuity services.

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1. Apple Notification Center Service (ANCS)

The Apple Notification Center Service (ANCS) enables an accessory (the Apple Watch) to retrieve notifications generated by a smart device (the Android phone).

Service Architecture

• ANCS Service UUID: 7905F431-B5CE-4E99-A40F-4B1E122D00D0
• Notification Source Characteristic: 9FBF120D-6301-42D9-8C58-25E699A21DBD (NOTIFY)
• Control Point Characteristic: 69D1D8F3-45E1-49A8-9821-9BBDFDAAD9D9 (WRITE)
• Data Source Characteristic: 22EAC6E9-24D6-4BB5-BE44-B36ACE7C7BFB (NOTIFY)

Flow Diagram

Android System Notification
           │
           ▼
iNA NotificationListenerService
           │
           ▼
[EventID: Added, CategoryID: Email/Message/Call, NotificationUID]
           │
           ▼ (Sent via Notification Source)
Apple Watch displays notification banner
           │
           ▼ (Optional user tap to read details)
Apple Watch sends [GetNotificationAttributes] via Control Point
           │
           ▼
iNA responds with [Title, Message, Date, App Identifier] via Data Source

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2. Apple Media Service (AMS)

The Apple Media Service (AMS) allows the Apple Watch to control audio playback on Android via the Digital Crown and touchscreen controls.

Service Architecture

• AMS Service UUID: 89D3502B-0F36-433A-8EF4-C502AD55F8DC
• Remote Command Characteristic: 9B3C81D8-57B1-4A0F-B867-0E05342F5B6F (WRITE / NOTIFY)
• Entity Update Characteristic: 2F7DD41B-30EA-43AE-9D5B-8CD599E26FDA (WRITE / NOTIFY)
• Entity Attribute Characteristic: C6B2F38C-23AB-46D8-A6AB-A3A870BBD5D7 (READ / WRITE)

Supported Media Controls

• Play / Pause / Toggle
• Next Track / Previous Track
• Volume Up / Volume Down (Digital Crown rotation)
• Track Title, Artist Name, and Duration synchronization to watch face

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3. Health & Sensor Telemetry

When connected, iNA reads real-time health sensor characteristics exposed by the Apple Watch GATT server:

• Heart Rate Service: UUID 0x180D (Characteristic 0x2A37 - Heart Rate Measurement)
• Battery Service: UUID 0x180F (Characteristic 0x2A19 - Battery Level)