From katzlbt@vuse.vanderbilt.edu mentions: I was working with software flow control (at 38400 baud) so the output to /dev/cufa resulted in a deadlock. If the modem does not dial but shows TR, check hardware flow control by using the device /dev/cufa with tip. If this results in a deadlock relace your modem cable, for now replace /dev/cufa with /dev/cua and change the baudrate to 19200.