[Thumbgps-devel] Progress in Shenzhen

[esr@thyrsus.com (Eric S. Raymond)]

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>>