Henning Meier-Geinitz wrote: > Hi, > > On Tue, Sep 13, 2005 at 07:36:19PM +0200, Bertrik Sikken wrote: > >>The protocol is weird because it seems to implement some kind of >>'USB-over-USB', i.e. the data payload of the USB control packets >>looks like another USB control packet. The payload size never >>appears to exceed 8 bytes. > > > Maybe this is one of the scanners which use a GL660 as a USB2.0 chip > and the GL646 (USB 1.1) as the real scan chip? This could explain the > USB-over-USB protocol.
Ok, that would explain a lot, but why would they do that? I don't think there is a GL646 chip in the scanner. The more I look at the usbsnoopy log, the more it looks similar to the hp5400 backend. This is probably good news because the hp5400 accepts a limited set of commands instead of dozens of writes to various registers. BTW, Daniel, I wrote a simple command line tool that talks to a hp5400 to query it for its version string. This can be useful as an example to do some low-level debugging in the early stages of hacking. You still need to modify it to use the USB-over-USB protocol, though, but I can help you with that. Kind regards, Bertrik