On Sunday, January 6, 2013 2:20:09 PM UTC+1, Chris Davison wrote:
How do the V7 and Butterfly rate in terms of being open and do

they work with XCSoar and K8000??

Some first-hand experience (I've contacted many vendors because I'm a voluntary XCSoar developer, and I co-wrote many of XCSoar's vario drivers):

LXNAV is extremely responsive and helpful. A few V7 protocol improvements were suggestions by me, and a new firmware was published after a few days. LXNAV has donated a V7 vario and a Nano logger to the XCSoar project. Thanks to that, XCSoar works very well with these products.

Note that LXNAV and LX Navigation are different companies; this cannot be pointed out often enough, as many people mix the two. LX Navigation has donated a MiniMap a few years ago, but getting technical information about the LX160/LX1600 product family was impossible for me, no reply to my emails. Therefore, no good XCSoar support.

Butterfly was very interested in XCSoar support, and has promised to donate a Vario to us, but that has not happened yet. XCSoar has no driver for the Butterfly Vario yet. If you're looking for a Vario to connect to XCSoar, wait until we are able to promise good interoperability. I'm positive that this will happen soon.

Another vario that works extremely well with XCSoar is the CAI302. Cambridge has published extensive and excellent protocol documentation before they (unfortunately) disappeared.

Its declared successor from ClearNav has no XCSoar support, and I suppose there will never be. ClearNav did not publish protocol documentation. I asked for documentation, but Richard Kellerman (who I'm not related to) rejected, saying his business is not interested in interoperability with XCSoar. Don't buy if you want to connect it to XCSoar (or any other free software).

Also don't buy Westerboer and SDI/Zander. Westerboer used copyright to take down VW1200 protocol documentation. SDI said (like ClearNav) they're not interested in XCSoar.