Bluetooth GATT Characteristic Reference
CGM Session Run Time (0x2AAB)
CGM Session Run Time is defined in the Bluetooth GATT XML specification with type org.bluetooth.characteristic.cgm_session_run_time and UUID 0x2AAB.
Quick Summary
Payload length is 4 bytes. 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 | CGM Session Run Time |
| UUID | 0x2AAB |
| Type | org.bluetooth.characteristic.cgm_session_run_time |
| XML Root | Characteristic |
| Source File | org.bluetooth.characteristic.cgm_session_run_time.xml |
| Field Count | 2 |
Field Specification
Parsed field definitions from the source XML value structure.
| Field | Requirement | Format | Unit | Exponent | Notes |
|---|---|---|---|---|---|
| CGM Session Run Time | Mandatory | uint16 | org.bluetooth.unit.time.hour | - | Typically the CGM Sensors have a limited run time where they are approved for by regulatory bodies. However this characteristic should enable a prediction of the run time depending on physiological effects in future devices. |
| E2E-CRC | C1 | uint16 | - | - | If the device supports E2E-safety (E2E-CRC-Supported bit is set in CGM Feature), the session run time is secured by a CRC calculated over all fields. |
Byte Layout and Decode
Payload length is 4 bytes.
function decodePayload(dataView, offset = 0) {
const cgm_session_run_time = dataView.getUint16(offset + 0, true);
const e2e_crc = dataView.getUint16(offset + 2, true);
return { cgm_session_run_time, e2e_crc };
}Use Cases and Integration Notes
BLE Telemetry
Map characteristic values into dashboards and alerts for device observability.
Firmware Regression
Compare decoded fields across builds to detect protocol or scaling changes.
App Integration
Build stable parsing paths that convert raw payloads into typed app models.
Implementation Checklist
- Validate payload length and mandatory fields before decode.
- Decode with Bluetooth-specified signedness, unit, and exponent handling.
- Convert units at presentation boundaries to avoid drift in business logic.
- Persist raw packets and decoded values for reproducible troubleshooting.
FAQ
What is CGM Session Run Time in Bluetooth GATT?
CGM Session Run Time is defined as a Bluetooth GATT characteristic entry with type org.bluetooth.characteristic.cgm_session_run_time and UUID 0x2AAB.
What UUID identifies CGM Session Run Time?
The UUID for CGM Session Run Time is 0x2AAB.
How should I parse CGM Session Run Time?
Payload length is 4 bytes.
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.