There are always questions about wireless transmission through the ANT protocol / ANT+ technology and the compatibility of different ANT+ capable terminals from different manufacturers.
What is ANT / ANT+ ?
The ANT protocol is only used by a few manufacturers. It is still used with e.g. pulse belts of the company Suunto. However, these ANT heart rate belts are not compatible with ANT+ end devices (e.g. Garmin). SRM supported this format for a long time with the Powercontrol computers of the older series. Even the current PC7 models can still receive heart rate via older ANT belts in addition to ANT+ heart rate. ANT+ is a wireless technology that allows different devices to communicate wirelessly with each other. This usually works without problems even with devices from different manufacturers. Most manufacturers today use ANT+ protocols.
What data can be transmitted with the ANT protocol?
The ANT+ technology allows the transmission of many different parameters. These are grouped into different profiles. The essential profiles for bike computers and power meters are Bicycle Power, Bicycle Speed & Cadence, Heart Rate Monitor and Multi Sport Speed & Distance. In addition, some end devices also support other ANT+ functions. Since there are always questions about the transfer of performance data, we want to take a closer look at the Bicyle Power profile and its functions.
This profile is used to transmit the performance data. Basically, there are four different measurement methods supported by ANT+ technology.
- Direct transfer of power
- Measurement of torque and rotational speed at the crank handle
- Measurement of torque and rotational speed on the impeller
These three methods are transmitted in the Bike PWR (Bike Power) data field. The fourth method is transmitted in the Bike CTF data field and is the Crank Torque Frequency (SRM mode).
Most headunits (bike computers for power meters) support the complete Bicyle Power Profile, i.e. the data field “Bike CTF” and “Bike PWR”.
Which data field is used by which power meter?
SRM is the only manufacturer that uses the data field “Bike CTF” for the transmission from the power meter. All other current ANT+ capable power meters (Quarq, Power2Max, CycleOps, etc.) use the data field “Bike PWR” for the measurement methods 1-3. Since almost all head units – with the exception of the SRM Powercontrol – support both formats, there are no compatibility problems.
Special features of the ANT+ protocol on the SRM PC 7
Unlike other devices (e.g. Garmin, etc…) the SRM PC7 can only receive the power data of the powermeter in “Bike CTF” (Bike Crank Torque Frequency) format. Therefore, the SRM PC7 is only compatible with power meters that support this transmission format. These are e.g. all SRM Powermeters and the Quarq Powermeters with a corresponding firmware update that unlocks the so-called German Achievement Mode (GAM).
Overview of all ANT+ devices
An overview of all ANT+ capable devices and the supported data formats can be found in the database on the ANT+ website. To do this, simply enter the relevant device or manufacturer in the search mask, click on it and under “more Infos” you will find all the information about it as well as compatible devices to choose from.