Hello. What is the serial driver that engines /dev/ttyS[0-4] ? is it 8250.c ? Can someone please explain to me what is the uart_add_one_port function ? And can someone please explain to me what is the data flow from the very low level (only receive/send)... ? Thank you. very much. Naziir. -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/