Hi, This device is seems to be based on some custom soc (arm9 or mips probably). I have tried to make some sense out of the data and have found out that shortest repeating pattern on completely white is 6 bits long. This pattern is 1010 00 or some other variation of same pattern of one's. I have also found out that when there's some other color on the input, this "exception" seems to start with 1010 01 or 1010 11. There's a good example on line 16 of 203.d For colored scans white is 1010 0000 0000 00.
I'm guessing that one 6 bit white accounts for 64 pixels. xres * yres / number of 6 bit sequences on one usb bulk packet / number of bulk packets. 2400 * 3000 / 187.0 / 599.0 = ~64.27 . This would seem more than just a coincidence Unfortunately completely black scan don't seem possible due to noise. I even tried killing leds that light the paper... Anyway, do you have any idea what compression algorithm could this be? usbmon dumps and images are at http://www.rasterburn.org/~aet/lx2480/ . I have stripped out everything but incoming bulk messages from that dump. Thanks -- Aapo Tahkola
