Extended Qualcomm Gobi features
And while I'm on the subject of bitching about hardware support, I had some time to poke at the Qualcomm Gobi hardware a bit more last week. With the aid of Dan Williams of Network Manager fame we identified[1] that the hardware actually does rather more than is obvious from the qcserial driver. There's two extra ports - one is for diagnostics, and the other claims to be an NMEA port. Poking support for these into qcserial is easy enough, but they don't seem especially chatty. The more interesting factor is that the fourth interface on the endpoint is a network device. This isn't unusual in modern hardware - PPP isn't a terribly helpful layering for data transfer, so most recent high speed data cards also provide support for some kind of network device. If you're lucky it's a spec-compliant cdc device. If you've got a gobi then it claims to be a vendor defined class and type and the .inf file for the driver claims that it's a proprietary cdc device. Testing this got cut short by us not actually having an account on Verizon[2], so we don't have any data dumps to work out what the framing looks like.
Interestingly, doing USB dumps revealed that Windows seemed to do everything via the network device. We didn't see any traffic from the other ports, even when attempting to turn on the GPS. So it may also have some magic out of band configuration that doesn't simply use AT commands.
If anyone has this stuff working under Windows, it'd be interesting to try getting some dumps to try to work out what's going on here.
[1] By the simple process of opening the device manager under Windows. Ahem.
[2] The test machine was a Vaio P, which came with a gobi but no SIM slot. Thanks, Sony. Thony.