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Comment by Nextgrid | Hacker News Reader

Does this go through their cloud or is it local-only? If it uses Shimano online services they have a point, but if it's local between devices that the cyclist had paid for, why should Shimano have any say in it?

Shimano are obviously assholes here, but Hammerhead are also disappointing for not standing their ground.

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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)

This is local only over a pretty simple communication protocol. Hammerhead had previously licensed that protocol, but Shimano cancelled the contract when Hammerhead were acquired by Shimano's largest competitor.

I'm not a lawyer so don't know if they _need_ to have a license for the protocol, but presumably they think they do.

> I'm not a lawyer so don't know if they _need_ to have a license for the protocol, but presumably they think they do.

They don't but they were probably using a licensed library they no longer have access to and would need to develop their own library first.

I wouldn't be surprised if they signed something explicit about not using the protocol without authorisation or something.

I have implemented the binary protocol from scratch many years ago. Amusingly, at the time, the data files downloaded from Garmins was pretty much the same protocol but just in a file. If you got a USB Ant+ receiver you got, as I recall, the same protocol from libusb.

I guess the problem is, once they have been given the protocol in a document covered by an NDA they can't use it outside that contract, even though they could trivially clean-room it.

They could easily outsource development to a company that is not under NDA right?

Every type of device that communicates over ANT has a profile. Shimano does not use the public shifting profile, but a closed (basically beta) profile.

Usually profiles start closed but eventually an open profile is published and devices move to it. Shimano failed to do so here.

I wonder if Shimano really cancelled of if there was some clause in the original agreement for preventing automatic handover in case of an acquisition that was invoked by some legal division at Shimano that simply doesn't have strategic decisions or customer happiness anywhere close of their job descriptions. Are they really actively trying to hurt a competitor or is it just some organizational automatism with nobody sufficiently in charge top correct course? I'm not exactly prone to defend Shimano (jumping through hoops to run Campagnolo), but I wouldn't be surprised if it all ended up with a big, genuine "sorry, we don't quite understand why exactly it happened"

Some (all?) parts of Shimano's Di2 system communicates via a proprietary protocol. The industry has standardized on ANT+, Shimano uses their own protocol. Hammerhead had a license agreement to use it. Shimano revoked (or opted to not renew) that license.

It is local, purely happen between the shimano di2 junction box on the bike and the bike computer.

There's no cloud. Shimano has a say because Shimano has decided to encrypt their ANT+ broadcast messages.

There may be a cloud. There's nothing to stop Hammerhead uploading data from the app to SRAM. That's probably what Shimano are worried about.

There is no cloud. This is how a bike computer communicates with the shifters on your bike.

Absolutely no cloud. All this stuff happens on-bike; it has to, because people frequently ride in places where there is no data service.

(Also, it's not clear how a cloud would help here. What we're talking about is allowing the groupset and the computer to share data in real time, to show on the head unit what gears are selected & etc. A cloud would just impose delay.)

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