Through a small wireless unit called EW-WU111, the Di2 system can communicate via ANT private protocol with different devices.
The EW-WU111 can be connected with your smart phone, tablet or PC and once connected it shows the gear and the current battery status. The connection between the two devices is made over the new E-Tube App via Bluetooth. A variety of possibilities are being offered such as functional assignments, shifter lever settings, multi- and synchro-shift settings and even the option of firmware upgrades on the components. Of course the connection between PC and the Di2 System can made as usual by using a USB cable.