kumandigital

Hello.. first i'm sorry for my bad english. i try to access serial port under debian linux box using php direct IO. <?php $fd = dio_open('/dev/ttyS0', O_RDWR | O_NOCTTY | O_NONBLOCK); dio_close($fd); ?> but i get warning like this: Warning: dio_open() [function.dio-open]: cannot open file /dev/ttyS0 with flags 2306 and permissions 0: Permission denied in /var/www/latihan/serial/test.php on line 2 Warning: dio_close() expects parameter 1 to be resource, boolean given in /var/www/latihan/serial/test.php on line 3 can you help me to solve my problem?? thanks before.