As far as I understand the bike computer connects to the group set (Di2) on the bike directly using either ANT+ or Bluetooth signal and no internet is needed fo

As far as I understand the bike computer connects to the group set (Di2) on the bike directly using either ANT+ or Bluetooth signal and no internet is needed for their communication. This is how I have used both. I think you can even DIY a device which connects to the group set. ANT+ is open access. https://en.m.wikipedia.org/wiki/ANT_(network) https://en.m.wikipedia.org/wiki/ANT_(network)