I have an avionics box that sends constant binary data. When I hooked the avionics box up to HyperTerminal, I can see this data stream. On the gumstix, I want to connect this device to /dev/ttyS0 but I noticed that getty was taking control of this port trying to produce a login prompt. Under /etc/inittab I modified the getty to release control of /dev/ttyS0 and now I have an open bidirectional ttyS0. I proved it by connecting HyperTerminal to /dev/ttyS0 on the gumstix and I could type characters from the HyperTerminal onto the gumstix and visa versa. When I hooked up the avionics box to the gumstix, and ran cat /dev/ttyS0 nothing shows up on my screen. I even tried tail /dev/ttyS0 and still nothing came cross the port. Shouldn't I see junk coming onto the gumstix from the avionics box? Anyone have any suggestions?