Short version: fix is in svn
Long version: I think I discovered the main reason that most people were getting a lot of "NO DATA" responses; you were using obdgpslogger after using someone else's software, and their software was changing settings on the device to work better for them.
obdgpslogger now sends an "ATZ" before doing anything else, when it first connects to a device. It also does the same thing when it shuts down, as a courtesy to other software that comes after.
It's worth nothing that unplugging and replugging the device would probably also have fixed the problem. Stupid thing for me not to have suggested, in retrospect.