One last thing. I started looking for any examples of serial routines that use epoll and, in the process, I ran across a discussion last year by some folks who were trying to get RS-232 communications working well enough to transfer binary files without corruption. One person wrote, "Don't use the Linux howto. It is old, not maintained and some of it is flat wrong." They went on to recommend a web resource which is still active to this very day. It is www.easysw.com/~mike/serial/serial.html Between that and the use of poll to alert on receipt of data, I should be able to come up with a better routine. The program I am writing is modular so I can work on the new serial engine and drop it in when it is ready and limp along with the older slow one for now. Thanks for all the suggestions. Martin McCormick WB5AGZ Stillwater, OK Systems Engineer OSU Information Technology Department Telecommunications Services Group _______________________________________________ Blinux-list mailing list Blinux-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/blinux-list