Bluetooth GATT Characteristic Reference

Alert Category ID (0x2A43)

org.bluetooth.characteristic.alert_category_id

The value of the characteristic is an unsigned 8 bit integer that has a fixed point exponent of 0. The Alert Category ID characteristic defines the predefined categories of messages as an enumeration.

Quick Summary

Payload length is 1 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	Alert Category ID
UUID	0x2A43
Type	org.bluetooth.characteristic.alert_category_id
XML Root	Characteristic
Source File	org.bluetooth.characteristic.alert_category_id.xml
Field Count	1

Field Specification

Parsed field definitions from the source XML value structure.

Field	Requirement	Format	Unit	Exponent	Notes
Category ID	Mandatory	uint8	-	-	-

Byte Layout and Decode

Payload length is 1 bytes.

function decodePayload(dataView, offset = 0) {
  const category_id = dataView.getUint8(offset + 0);
  return { category_id };
}

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 Alert Category ID in Bluetooth GATT?

Alert Category ID is defined as a Bluetooth GATT characteristic entry with type org.bluetooth.characteristic.alert_category_id and UUID 0x2A43.

What UUID identifies Alert Category ID?

The UUID for Alert Category ID is 0x2A43.

How should I parse Alert Category ID?