How to connect your Di2 system to your Windows computer
Modern Di2 is basically a couple of controllers and servo motors that communicate with each other using the EW-SD50 wires. Shimano lets end-users configure their own Di2 systems using their e-tube project software. This page explains how to connect your bike to your computer.
Connecting a Di2 bike to a Windows computer is done via the charging / interface port on the Junction A. Note that if your bike uses the older SM-EW67A junction then you will not be able to connect your bike using the charger.
In that case you need the SM-SM-PCE1/SM-PCE02 diagnostics device.
You probably know where the charging port is - but just in case you don't, have a look at this image:
Connect using e-Tube Project
Plug your charger into the junction box and connect the other end to your computer – the order doesn’t really matter, but I tend to plug the connector into the bike first. Start the e-Tube Project software. Select your bike type (road, MTB, Urban/City, STEPS e-bike or ‘other e-bike’) system. Your bike type is determined by the derailleurs installed on the bike.
It’ll then tell you that charging has stopped because you’ve connected the bike to the computer and started the software.
If you’re using a road bike it will also ask you whether you’ve connected satellite shifters to your main shifters. Answer the questions and it’ll complete the connection.
This is what you’ll see once a connection has been made.