Thanks, tried concatenating the send before sending the command to the phabrix... but it isn't helping. Despite peppering the code with print statements, it definitely never hangs while inside the subroutine, so the Phabrix doesn't seem to be the issue. rather it seems to hang if it receives another message from the lightspace device before it's done sending the commands to the phabrix... somehow recieving another message too early makes it stop executing once the phabrix subroutine is finished.

To answer your question about the phabrix though, it does not require any sort of line ending. As soon as it recieves a 20 byte message, it responds ACK or NAK or sometimes not at all, and closes the socket.

It must have to do with the way I'm reading from the lightspace.

-ben