Indoor Bike Data (0x2AD2): byte layout
GATT characteristic · org.bluetooth.characteristic.indoor_bike_data · read from the Bluetooth SIG’s repository on 2026-10-17 · commit 408f4a0 (2026-10-14)
Indoor Bike Data is Bluetooth GATT characteristic 0x2AD2, org.bluetooth.characteristic.indoor_bike_data in the Bluetooth SIG's assigned numbers. The SIG's GATT Specification Supplement file lays its value out as 16 fields: Flags, Instantaneous Speed, Average Speed, Instantaneous Cadence, Average Cadence and 11 more. The first, Flags, is a boolean[16]; 15 of the others are present only when a bit of it is set as the field's text states, so after the first of those, a field's offset depends on which bits are set.
- UUID
- 0x2AD2
- Identifier
org.bluetooth.characteristic.indoor_bike_data- The SIG’s description
- The Indoor Bike Data characteristic is used to represent data related to the use of an indoor bike.The structure of this characteristic is defined below.
- Service the SIG’s files tie it to
- None: no file in the repository lists this characteristic under a service.
- Source file
- gss/org.bluetooth.characteristic.indoor_bike_data.yaml
Byte layout: 16 fields
In the order the SIG’s structure lists them. Type and size are as published; sizes count octets except where a struct is marked as sized in bits. The offset is printed only where every earlier field has a fixed size; where an earlier field can be absent or vary, the cell names what it depends on. “Present when” is read from the field’s own “Present if” line, shown in full in the field notes below.
| Offset | Field | Type | Size | Present when | Unit |
|---|---|---|---|---|---|
| 0 | Flags | boolean[16] | 2 | Always (fixed size) | — |
| 2 | Instantaneous Speed | uint16 | 0 or 2 | Bit 0 of Flags is 0 | velocity (kilometre per hour)org.bluetooth.unit.velocity.kilometre_per_hour |
| Depends on Flags (bit 0) | Average Speed | uint16 | 0 or 2 | Bit 1 of Flags is 1 | velocity (kilometre per hour)org.bluetooth.unit.velocity.kilometre_per_hour |
| Depends on Flags (bits 0 and 1) | Instantaneous Cadence | uint16 | 0 or 2 | Bit 2 of Flags is 1 | angular velocity (revolution per minute)org.bluetooth.unit.angular_velocity.revolution_per_minute |
| Depends on Flags (bits 0, 1 and 2) | Average Cadence | uint16 | 0 or 2 | Bit 3 of Flags is 1 | angular velocity (revolution per minute)org.bluetooth.unit.angular_velocity.revolution_per_minute |
| Depends on Flags (bits 0, 1, 2 and 3) | Total Distance | uint24 | 0 or 3 | Bit 4 of Flags is 1 | length (metre)org.bluetooth.unit.length.metre |
| Depends on Flags (bits 0, 1, 2, 3 and 4) | Resistance Level | uint8 | 0 or 1 | Bit 5 of Flags is 1 | unitlessorg.bluetooth.unit.unitless |
| Depends on Flags (bits 0, 1, 2, 3, 4 and 5) | Instantaneous Power | sint16 | 0 or 2 | Bit 6 of Flags is 1 | power (watt)org.bluetooth.unit.power.watt |
| Depends on Flags (bits 0, 1, 2, 3, 4, 5 and 6) | Average Power | sint16 | 0 or 2 | Bit 7 of Flags is 1 | power (watt)org.bluetooth.unit.power.watt |
| Depends on Flags (bits 0, 1, 2, 3, 4, 5, 6 and 7) | Total Energy | uint16 | 0 or 2 | Bit 8 of Flags is 1 | energy (kilogram calorie)org.bluetooth.unit.energy.kilogram_calorie |
| Depends on Flags (bits 0, 1, 2, 3, 4, 5, 6, 7 and 8) | Energy Per Hour | uint16 | 0 or 2 | Bit 8 of Flags is 1 | energy (kilogram calorie)org.bluetooth.unit.energy.kilogram_calorie |
| Depends on Flags (bits 0, 1, 2, 3, 4, 5, 6, 7 and 8) | Energy Per Minute | uint8 | 0 or 1 | Bit 8 of Flags is 1 | energy (kilogram calorie)org.bluetooth.unit.energy.kilogram_calorie |
| Depends on Flags (bits 0, 1, 2, 3, 4, 5, 6, 7 and 8) | Heart Rate | uint8 | 0 or 1 | Bit 9 of Flags is 1 | period (beats per minute)org.bluetooth.unit.period.beats_per_minute |
| Depends on Flags (bits 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9) | Metabolic Equivalent | uint8 | 0 or 1 | Bit 10 of Flags is 1 | metabolic equivalentorg.bluetooth.unit.metabolic_equivalent |
| Depends on Flags (bits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10) | Elapsed Time | uint16 | 0 or 2 | Bit 11 of Flags is 1 | time (second)org.bluetooth.unit.time.second |
| Depends on Flags (bits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and 11) | Remaining Time | uint16 | 0 or 2 | Bit 12 of Flags is 1 | time (second)org.bluetooth.unit.time.second |
Field notes
Each field’s text in the SIG’s file, line by line.
- Flags boolean[16] · 2
- See Flags
- Instantaneous Speed uint16 · 0 or 2
- Base Unit: org.bluetooth.unit.velocity.kilometre_per_hourRepresented values: M = 1, d = -2, b = 0Unit is 1/100 of a kilometer per hourThe Instantaneous Speed field represents the instantaneous speed of the user.Present if bit 0 of Flags field is set to 0
- Average Speed uint16 · 0 or 2
- Base Unit: org.bluetooth.unit.velocity.kilometre_per_hourRepresented values: M = 1, d = -2, b = 0Unit is 1/100 of a kilometer per hourThe Average Speed field represents the average speed since the beginning of the training session.Present if bit 1 of Flags field is set to 1
- Instantaneous Cadence uint16 · 0 or 2
- Base Unit: org.bluetooth.unit.angular_velocity.revolution_per_minuteRepresented values: M = 1, d = 0, b = -1Unit is 1/2 of a revolution per minuteThe Instantaneous Cadence field represents the instantaneous cadence of the user.Present if bit 2 of Flags field is set to 1
- Average Cadence uint16 · 0 or 2
- Base Unit: org.bluetooth.unit.angular_velocity.revolution_per_minuteRepresented values: M = 1, d = 0, b = -1Unit is 1/2 of a revolution per minuteThe Average Speed field represents the average cadence since the beginning of the training session.Present if bit 3 of Flags field is set to 1
- Total Distance uint24 · 0 or 3
- Unit: org.bluetooth.unit.length.metreThe Total Distance field represents the total distance reported by the Server since the beginning of the training session.Present if bit 4 of Flags field is set to 1
- Resistance Level uint8 · 0 or 1
- Base Unit: org.bluetooth.unit.unitlessRepresented values: M = 1, d = 1, b = 0Unit is 1The Resistance Level field represents the value of the current value of the resistance level of the Server.Present if bit 5 of Flags field is set to 1
- Instantaneous Power sint16 · 0 or 2
- Unit: org.bluetooth.unit.power.wattThe Instantaneous Power field represents the value of the instantaneous power measured by the Server.Present if bit 6 of Flags field is set to 1
- Average Power sint16 · 0 or 2
- Unit: org.bluetooth.unit.power.wattThe Average Power field represents the value of the average power measured by the Server since the beginning of the training session.Present if bit 7 of Flags field is set to 1
- Total Energy uint16 · 0 or 2
- Unit: org.bluetooth.unit.energy.kilogram_calorieThe Total Energy field represents the total expended energy of a user since the training session has started.Present if bit 8 of Flags field is set to 1
- Energy Per Hour uint16 · 0 or 2
- Unit: org.bluetooth.unit.energy.kilogram_calorieThe Energy per Hour field represents the average expended energy of a user during a period of one hour.Present if bit 8 of Flags field is set to 1
- Energy Per Minute uint8 · 0 or 1
- Unit: org.bluetooth.unit.energy.kilogram_calorieThe Energy per Minute field represents the average expended energy of a user during a period of one minute.Present if bit 8 of Flags field is set to 1
- Heart Rate uint8 · 0 or 1
- Unit: org.bluetooth.unit.period.beats_per_minuteThe Heart Rate field represents the current heart rate value of the user (e.g., measured via the contact heart rate or any other means).Present if bit 9 of Flags field is set to 1
- Metabolic Equivalent uint8 · 0 or 1
- Base Unit: org.bluetooth.unit.metabolic_equivalentRepresented values: M = 1, d = -1, b = 0Unit is 1/10 metabolic equivalentThe Metabolic Equivalent field represents the metabolic equivalent of the user.Present if bit 10 of Flags field is set to 1
- Elapsed Time uint16 · 0 or 2
- Unit: org.bluetooth.unit.time.secondThe Elapsed Time field represents the elapsed time of a training session since the training session has started.Present if bit 11 of Flags field is set to 1
- Remaining Time uint16 · 0 or 2
- Unit: org.bluetooth.unit.time.secondThe Remaining Time field represents the remaining time of a selected training session.Present if bit 12 of Flags field is set to 1
Flags and value tables
The definitions the SIG’s file gives for its fields, every row as published. On a flags table the last column lists the fields whose “Present if” line names that bit.
Flags
The bits of this field are defined below.
| Bit | Description | Fields its condition names |
|---|---|---|
| 0 | More Data | Instantaneous Speed when 0 |
| 1 | Average Speed present | Average Speed when 1 |
| 2 | Instantaneous Cadence present | Instantaneous Cadence when 1 |
| 3 | Average Cadence present | Average Cadence when 1 |
| 4 | Total Distance present | Total Distance when 1 |
| 5 | Resistance Level present | Resistance Level when 1 |
| 6 | Instantaneous Power present | Instantaneous Power when 1 |
| 7 | Average Power present | Average Power when 1 |
| 8 | Expended Energy present | Total Energy when 1Energy Per Hour when 1Energy Per Minute when 1 |
| 9 | Heart Rate present | Heart Rate when 1 |
| 10 | Metabolic Equivalent present | Metabolic Equivalent when 1 |
| 11 | Elapsed Time present | Elapsed Time when 1 |
| 12 | Remaining Time present | Remaining Time when 1 |
| 13–15 | Reserved for Future Use | — |
Guides on this site
The connected-device guides that name 0x2AD2:
Questions
- What is the UUID of the Indoor Bike Data characteristic?
- 0x2AD2. The Bluetooth SIG's characteristic_uuids.yaml lists Indoor Bike Data as 0x2AD2 with the identifier org.bluetooth.characteristic.indoor_bike_data. No file in the SIG's repository ties it to a service: the repository lists service and characteristic UUIDs separately.
- Which Indoor Bike Data fields are optional?
- 15 of its 16 fields have a published size that can be zero: Instantaneous Speed (0 or 2; Present if bit 0 of Flags field is set to 0); Average Speed (0 or 2; Present if bit 1 of Flags field is set to 1); Instantaneous Cadence (0 or 2; Present if bit 2 of Flags field is set to 1); Average Cadence (0 or 2; Present if bit 3 of Flags field is set to 1); Total Distance (0 or 3; Present if bit 4 of Flags field is set to 1); Resistance Level (0 or 1; Present if bit 5 of Flags field is set to 1); Instantaneous Power (0 or 2; Present if bit 6 of Flags field is set to 1); Average Power (0 or 2; Present if bit 7 of Flags field is set to 1); Total Energy (0 or 2; Present if bit 8 of Flags field is set to 1); Energy Per Hour (0 or 2; Present if bit 8 of Flags field is set to 1); Energy Per Minute (0 or 1; Present if bit 8 of Flags field is set to 1); Heart Rate (0 or 1; Present if bit 9 of Flags field is set to 1); Metabolic Equivalent (0 or 1; Present if bit 10 of Flags field is set to 1); Elapsed Time (0 or 2; Present if bit 11 of Flags field is set to 1); Remaining Time (0 or 2; Present if bit 12 of Flags field is set to 1). Flags (2) has a fixed size.
- What units does Indoor Bike Data use?
- The SIG's text names a unit for 15 of the 16 fields: Instantaneous Speed: velocity (kilometre per hour) (org.bluetooth.unit.velocity.kilometre_per_hour); Average Speed: velocity (kilometre per hour) (org.bluetooth.unit.velocity.kilometre_per_hour); Instantaneous Cadence: angular velocity (revolution per minute) (org.bluetooth.unit.angular_velocity.revolution_per_minute); Average Cadence: angular velocity (revolution per minute) (org.bluetooth.unit.angular_velocity.revolution_per_minute); Total Distance: length (metre) (org.bluetooth.unit.length.metre); Resistance Level: unitless (org.bluetooth.unit.unitless); Instantaneous Power: power (watt) (org.bluetooth.unit.power.watt); Average Power: power (watt) (org.bluetooth.unit.power.watt); Total Energy: energy (kilogram calorie) (org.bluetooth.unit.energy.kilogram_calorie); Energy Per Hour: energy (kilogram calorie) (org.bluetooth.unit.energy.kilogram_calorie); Energy Per Minute: energy (kilogram calorie) (org.bluetooth.unit.energy.kilogram_calorie); Heart Rate: period (beats per minute) (org.bluetooth.unit.period.beats_per_minute); Metabolic Equivalent: metabolic equivalent (org.bluetooth.unit.metabolic_equivalent); Elapsed Time: time (second) (org.bluetooth.unit.time.second); Remaining Time: time (second) (org.bluetooth.unit.time.second).
- What do the bits of the Indoor Bike Data Flags field mean?
- The SIG defines them as: bit 0, More Data (Instantaneous Speed when 0); bit 1, Average Speed present (Average Speed when 1); bit 2, Instantaneous Cadence present (Instantaneous Cadence when 1); bit 3, Average Cadence present (Average Cadence when 1); bit 4, Total Distance present (Total Distance when 1); bit 5, Resistance Level present (Resistance Level when 1); bit 6, Instantaneous Power present (Instantaneous Power when 1); bit 7, Average Power present (Average Power when 1); bit 8, Expended Energy present (Total Energy when 1, Energy Per Hour when 1, Energy Per Minute when 1); bit 9, Heart Rate present (Heart Rate when 1); bit 10, Metabolic Equivalent present (Metabolic Equivalent when 1); bit 11, Elapsed Time present (Elapsed Time when 1); bit 12, Remaining Time present (Remaining Time when 1). The remaining bits are reserved for future use.
Source
Read on 2026-10-17 from gss/org.bluetooth.characteristic.indoor_bike_data.yaml and assigned_numbers/uuids/characteristic_uuids.yaml in the Bluetooth SIG’s public repository (branch main, commit 408f4a0, committed 2026-10-14), by scripts/fetch-bluetooth-gatt.mjs. The file’s notice says it is proprietary to Bluetooth SIG, that furnishing it grants no licence, and that it is subject to change without notice; it is © Bluetooth SIG, Inc., and its text is quoted here for identification. Generated by AIFitnessAPI, which is not affiliated with Bluetooth SIG; the SIG’s file remains the authority. The full notice and the conventions used on these pages are on the reference hub.