All Bluetooth 4.1 headsets have two modes for communicating between each other using Bluetooth, Normal Intercom Mode and HD Intercom Mode.
Normal Intercom Mode allows for intercom communication between multiple headsets (up to 8) over long distances such as the 20S EVO which can be used to talk to someone up to 1.2 miles (2.0 km) away in open terrain and with line of sight.
HD Intercom Mode allows for higher quality intercom communication by combining the Advanced Audio Distribution Profile (A2DP) with the Intercom Profile. By combining these two Bluetooth profiles together for higher quality communication, the amount of headsets that can be connected together is limited to 2 and range between each of the headsets is reduced compared to the range of Normal Intercom Mode.
- Bluetooth 3.0 headsets only support Normal Intercom Mode.
- All Bluetooth 4.1 headsets support Normal Intercom Mode and HD Intercom Mode.
- HD Intercom Mode is enabled by default on all Bluetooth 4.1 headsets and can be disabled through the Sena Device Manager or the Sena Utility App.
- The headsets will automatically switch to Normal Intercom Mode when a third person is added to the Bluetooth intercom group.