We basically want to make our device compatible with as many Smart phones as possible so I wonder whether it possible to have a device that is a peripheral to listen to both, BLE and Bluetooth Classic Connections at the same time
With LinkIt ONE HDK/SDK, the above scenario is achievable. The Bluetooth 2.1 and Bluetooth GATT (4.0) on LinkIt ONE platform run independently. Currently, the LinkIt ONE platform supports SPP (2.1) and GATT (4.0) profiles. You can start to try both the SPP and GATT at the same time on the board, by instantiating the objects of BT Basic and BLE separately.