[Thumbgps-devel] Progress in Shenzhen

tz tz2026 at gmail.com
Sat Mar 17 17:23:09 EDT 2012


Note the 731-r is venus 5, the ones I've used are venus 6, but skytraq
seems consistent.

Would you happen to know if the unitraq is 20hz (venus 638) or 10hz (634)?

Note they could have a populateable 0 ohm jumper if they wanted it
optional, but dcd or ri shouldn't interfere with generic gps software.
On Mar 17, 2012 10:19 AM, "Eric S. Raymond" <esr at thyrsus.com> wrote:

> Of the 5 companies I contacted, two - NaviSys and UniTraq - have
> gotten back to me, confirmed that their USB GPS dongles do not ship 1PPS,
> and expressed interest in the possibility of customizing a product for
> us.  A third, Xucai Technologies, responded without bringing up the
> possibility of an OEM/ODM product.  This is as good a response rate
> as I was expecting.
>
> Three devices are under discussion.
>
> One NaviSys device is the GR-300, bsed on uBlox 6 with integral USB
> interface. I think this one is actually a non-starter as it would
> require fiddling with the uBlox firmware to get the chip to ship
> 1PPS notifications.
>
> The other NaviSys device is the GR-300: SiRFIII + PL2303.  The UniTraq
> device is the UD-731R: SkyTraq + CP-2102.  Both adapters have full
> Linux support and have DCD pins.  Both chipsets emit 1PPS.  Neither
> device connects the 1PPS pin to the adapter DCD.
>
> I am pitching both companies the idea that with one added PCB trace
> they could sell to a sizeable untapped market of people with
> applications like network tomography and Stratum 1 NTP servers.
> I've told them we're willing to help them test and qualify the
> product if they'll sell the results back to us at a price
> that is reasonable for a hundred-unit deployment.
>
> It's early in the negotiations yet, but things look promising.  These
> outfits are clearly used to doing ODM/OEM business - the only real
> difficulty I'm having is explaining why I think this mod will work,
> because these people don't know the odd corners of the USB spec
> involved.
>
> In the process of writing my explanations I've done more research
> (including reading the Linux PL2303 driver source code and grokking
> how USB handshake control messages are handled there) and my
> confidence that the mod actually will work has increased.
>
> I think I have at least one more plausible company - GlobalSat - to
> poke about this if neither NaviSys or UniTraq follows through. More
> might be findable through alibaba.com
> --
>                                                >>esr>>
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