> > Do you know what the three interfaces are used for by the way? And do you > > have any idea about whether the other products using the same PID also > > have six bulk endpoints (three tty interfaces)? > > Yes. There are three [mostly] independent terminals. The older > devices were normally used with two or three serial ports, and people > got used to this. While I suppose they could be used to allow three > users to do separate things on the device, I am using one for a > bidirectional control port, (sending commands and getting > acknowledgements) and a second one I am using to listen to binary > output from the GPS (which makes parsing a little easier). [you can > create "log" commands that send the data to a different port. So on > USB1 I can send the command "log usb2 rangeb ontime 1" which will > display "OK" on usb1 and give me a fresh command prompt, and also > causes a binary range message to appear on usb2 every 1 second.] > > A lot of people [especially ones who have lots of experience with old > serial-interface GPS devices] will connect one of the ports from one > device to another device (generally with some sort of radio in > between) and make them talk to each other. Think of a surveyor > putting one GPS receiver on a calibrated marker which sends > differential information to other receivers so they can more > accurately correct for common errors (such as local ionospheric > effects and satellite errors). Now days this is frequently done by > attaching a listener to the appropriate port (say /dev/ttyUSB2), and > it reflects to a remote webserver-based reflector (wireless internet > access is much cheaper and more useful than a dedicated commercial > radio). While the two are talking to each other you still need an > interface to command them, hence the two or three serial ports (third > was for daisy chaining, I think). > > Anyway, every NovaTel device I have ever seen thinks it has triplets > of each interface type, [even when the third serial port did not have > a physical device][yes, even the ones with a built in Ethernet device > have internal "icom1", "icom2", and "icom3" interface names for > sending IP traffic.] > > For testing your patch I intend on just opening three minicom > instances, once to each /dev/ttyUSB[0-2], and doing local ASCII logs > ("log version once"; if you do not provide an interface it defaults to > the one you sent the command on). Thanks for the info. I'm responding to this mail with two patches adding a new "simple" driver for Novatel Wireless GPS receivers for you to test. Let me know how it works. Thanks, Johan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html