Bluetooth GATT Service Reference
User Data (0x181C)
The User Data Service (UDS) exposes user-related data in the sports and fitness environment. This allows remote access and update of user data by a Client as well as the synchronization of user data between a Server and a Client.
Quick Summary
No fixed value payload is declared in this XML; this entry defines metadata and profile structure. This page is generated from official GATT XML and presented as implementation-ready guidance.
At a Glance
Key reference details for BLE implementation, interoperability testing, and AI-assisted troubleshooting.
| Property | Value |
|---|---|
| Name | User Data |
| UUID | 0x181C |
| Type | org.bluetooth.service.user_data |
| XML Root | Service |
| Source File | org.bluetooth.service.user_data.xml |
| Field Count | 0 |
Characteristic List
Characteristics declared by this service profile entry.
| Characteristic | Type | Requirement | Properties |
|---|---|---|---|
| First Name | org.bluetooth.characteristic.first_name | C1 | Read, Write |
| Last Name | org.bluetooth.characteristic.last_name | C1 | Read, Write |
| Email Address | org.bluetooth.characteristic.email_address | C1 | Read, Write |
| Age | org.bluetooth.characteristic.age | C1 | Read, Write |
| Date of Birth | org.bluetooth.characteristic.date_of_birth | C1 | Read, Write |
| Gender | org.bluetooth.characteristic.gender | C1 | Read, Write |
| Weight | org.bluetooth.characteristic.weight | C1 | Read, Write |
| Height | org.bluetooth.characteristic.height | C1 | Read, Write |
| VO2 Max | org.bluetooth.characteristic.vo2_max | C1 | Read, Write |
| Heart Rate Max | org.bluetooth.characteristic.heart_rate_max | C1 | Read, Write |
| Resting Heart Rate | org.bluetooth.characteristic.resting_heart_rate | C1 | Read, Write |
| Maximum Recommended Heart Rate | org.bluetooth.characteristic.maximum_recommended_heart_rate | C1 | Read, Write |
| Aerobic Threshold | org.bluetooth.characteristic.aerobic_threshold | C1 | Read, Write |
| Anaerobic Threshold | org.bluetooth.characteristic.anaerobic_threshold | C1 | Read, Write |
| Sport Type for Aerobic and Anaerobic Thresholds | org.bluetooth.characteristic.sport_type_for_aerobic_and_anaerobic_thresholds | C1 | Read, Write |
| Date of Threshold Assessment | org.bluetooth.characteristic.date_of_threshold_assessment | C1 | Read, Write |
| Waist Circumference | org.bluetooth.characteristic.waist_circumference | C1 | Read, Write |
| Hip Circumference | org.bluetooth.characteristic.hip_circumference | C1 | Read, Write |
| Fat Burn Heart Rate Lower Limit | org.bluetooth.characteristic.fat_burn_heart_rate_lower_limit | C1 | Read, Write |
| Fat Burn Heart Rate Upper Limit | org.bluetooth.characteristic.fat_burn_heart_rate_upper_limit | C1 | Read, Write |
| Aerobic Heart Rate Lower Limit | org.bluetooth.characteristic.aerobic_heart_rate_lower_limit | C1 | Read, Write |
| Aerobic Heart Rate Upper Limit | org.bluetooth.characteristic.aerobic_heart_rate_upper_limit | C1 | Read, Write |
| Anaerobic Heart Rate Lower Limit | org.bluetooth.characteristic.anaerobic_heart_rate_lower_limit | C1 | Read, Write |
| Anaerobic Heart Rate Upper Limit | org.bluetooth.characteristic.anaerobic_heart_rate_upper_limit | C1 | Read, Write |
| Five Zone Heart Rate Limits | org.bluetooth.characteristic.five_zone_heart_rate_limits | C1 | Read, Write |
| Three Zone Heart Rate Limits | org.bluetooth.characteristic.three_zone_heart_rate_limits | C1 | Read, Write |
| Two Zone Heart Rate Limit | org.bluetooth.characteristic.two_zone_heart_rate_limit | C1 | Read, Write |
| Database Change Increment | org.bluetooth.characteristic.database_change_increment | Mandatory | Read, Write, Notify |
| User Index | org.bluetooth.characteristic.user_index | Mandatory | Read |
| User Control Point | org.bluetooth.characteristic.user_control_point | Mandatory | Write, Indicate |
| Language | org.bluetooth.characteristic.language | C1 | Read, Write |
Use Cases and Integration Notes
Service Discovery
Use this definition to validate discovered services and expected characteristics during BLE onboarding.
Profile Compliance
Cross-check required characteristics and properties for conformance and QA automation.
App Capability Gating
Drive feature availability in apps based on whether service-level requirements are present.
Implementation Checklist
- Validate the service UUID during discovery before reading characteristic metadata.
- Ensure mandatory characteristics exist and expose expected properties.
- Map declaration data to app feature flags before attempting writes/subscriptions.
- Record mismatches between firmware tables and expected profile definitions in logs.
Dependencies
- This service is not dependent upon any other services.
FAQ
What is User Data in Bluetooth GATT?
User Data is defined as a Bluetooth GATT service entry with type org.bluetooth.service.user_data and UUID 0x181C.
What UUID identifies User Data?
The UUID for User Data is 0x181C.
How should I parse User Data?
Parse the structure and requirements from the XML definition, then enforce format/requirement rules in your BLE stack.
Where does this definition come from?
This page is generated from the Bluetooth SIG mirror XML in the oesmith/gatt-xml repository.
How does this page support BLE implementation?
The page combines structured tables, practical Q&A, and JSON-LD metadata to help teams validate integrations and troubleshoot consistently.