1) My experience with rt_com was that it works fine after calling something like rt_com_init() (don't know how your source works but it may help) 2) To generate a on UART signal with a UART I would not use TxD / RxD but RTS/CTS or so :) (I allready had luck to manage SMPTE code (4Khz) via LPT) Jens --- [rtl] --- To unsubscribe: echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED] ---- For more information on Real-Time Linux see: http://www.rtlinux.org/~rtlinux/