Bluetooth GATT Characteristic Reference

CGM Specific Ops Control Point (0x2AAC)

org.bluetooth.characteristic.cgm_specific_ops_control_point

The CGM Specific Ops Control Point encapsulates all functionality and mechanisms that are unique to a CGM-device. This control point is used with a service to provide CGM specific functionality and the ability to change CGM specific settings of the device. This includes functions like setting the CGM Communication Interval or the sending a calibration value to the device. The criterion in the Operand field is defined by the service that references this characteristic

Quick Summary

Payload length is profile-defined or variable based on field formats. 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 Specific Ops Control Point
UUID	0x2AAC
Type	org.bluetooth.characteristic.cgm_specific_ops_control_point
XML Root	Characteristic
Source File	org.bluetooth.characteristic.cgm_specific_ops_control_point.xml
Field Count	11

Field Specification

Parsed field definitions from the source XML value structure.

Field	Requirement	Format	Unit	Exponent	Notes
Op Code	Mandatory	uint8	-	-	-
Op Code - Response Codes	Mandatory	uint8	-	-	-
Operand	Mandatory	variable	-	-	Value defined per Service
E2E-CRC	C1	uint16	-	-	If the device supports E2E-safety (E2E-CRC-Supported bit is set in CGM Feature), the specific ops control point is secured by a CRC calculated over all fields. Refer to CGM Service specification.
Calibration Value - Glucose Concentration of Calibration	Mandatory	SFLOAT	org.bluetooth.unit.mass_density.milligram_per_decilitre	0	See Note number 2 below.
Calibration Value - Calibration Time	Mandatory	uint16	org.bluetooth.unit.time.minute	0	See Note number 2 below.
Calibration Value - Calibration Type	Mandatory	4bit	-	-	See Note number 2 below.
Calibration Value - Calibration Sample Location	Mandatory	4bit	-	-	See Note number 2 below.
Calibration Value - Next Calibration Time	Mandatory	uint16	org.bluetooth.unit.time.minute	0	See Note number 2 below.
Calibration Value - Calibration Data Record Number	Mandatory	uint16	-	-	See Note number 2 below.
Calibration Value - Calibration Status	Mandatory	8bit	-	-	See Note number 2 below.

Bit Map

Bit-level enumerations extracted from the XML BitField definition.

Field	Bit	Size	Name	0 Means	1 Means
Calibration Value - Calibration Status	0	1	Calibration Data rejected (Calibration failed)	False	True
Calibration Value - Calibration Status	1	1	Calibration Data out of range	False	True
Calibration Value - Calibration Status	2	1	Calibration Process Pending	False	True

Byte Layout and Decode

Payload length is profile-defined or variable based on field formats.

function decodePayload(dataView, offset = 0) {
  const op_code = dataView.getUint8(offset + 0);
  const op_code_response_codes = dataView.getUint8(offset + 1);
  // Parse operand (variable) according to Bluetooth format rules.
  const e2e_crc = dataView.getUint16(offset + 2, true);
  // Parse calibration_value_glucose_concentration_of_calibration (SFLOAT) according to Bluetooth format rules.
  const calibration_value_calibration_time = dataView.getUint16(offset + 4, true);
  // Parse calibration_value_calibration_type (4bit) according to Bluetooth format rules.
  // Parse calibration_value_calibration_sample_location (4bit) according to Bluetooth format rules.
  const calibration_value_next_calibration_time = dataView.getUint16(offset + 6, true);
  const calibration_value_calibration_data_record_number = dataView.getUint16(offset + 8, true);
  return { op_code, op_code_response_codes, operand, e2e_crc, calibration_value_glucose_concentration_of_calibration, calibration_value_calibration_time };
}

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 Specific Ops Control Point in Bluetooth GATT?

CGM Specific Ops Control Point is defined as a Bluetooth GATT characteristic entry with type org.bluetooth.characteristic.cgm_specific_ops_control_point and UUID 0x2AAC.

What UUID identifies CGM Specific Ops Control Point?

The UUID for CGM Specific Ops Control Point is 0x2AAC.

How should I parse CGM Specific Ops Control Point?