Hi, I made a mistake in posting and so it seems that there is no problem for Udo (Sorry Gert). The problem is that I can not dial out if mgetty is running. May be the pppd program do not uses proper locking?! I switched to use /dev/ttyS0 for pppd (instead of /dev/modem) but the problem remains. Any suggestions? Udo P.S. Thanks for the detailed answer to my posting!