First time subsurace usage surprises

[Lutz Vieweg]

On 08/01/2012 01:00 AM, Linus Torvalds wrote:
> Do you see any other way to do a two-pin signal+ground thing out of a
> standard serial line?

Not one that would be guaranteed to work, but this circuit:
http://web.archive.org/web/20070419042834im_/http://insel.heim.at/malediven/350052/g/eon2_1.gif
is reported to be compatible with a wider range of PCs, using
the Maxim MAX232 that integrates a charge pump to achieve
useful signal levels under difficult circumstances.

> Anyway, I'm not actually much of a hw person, but it all looks pretty
> hacky to me. But if you want minimal electrical pins sticking out of
> the dive computer, two is the lowest number you can do..

Suunto could have used a tiny IR emitting diode, which seems
easy to seal against pressure.

Regards,

Lutz Vieweg