>Thanks for helping me with this problem.
>
>I am using the DG-100 datalogger from GlobalSat. As far as I can tell from the documentation the company sent me, it can only work with a baud rate of 115200.
>
>The puzzling thing to me is that I can read data from the device with no problem if I type each command into the command window, but get nothing when I try to do the same thing from inside a program.

This hints to a need to wait for an ACK or something to come back from the device. When you do these manually, you're slow enough. Your code isn't waiting - maybe it should?