You need to verify that the serial port are correctly "active" in the server's BIOS/CMOS

Then, you need check to see if the serial ports are set up within SCO 5.0.5 with 'mkdev serial'

After, you need to know what type of serial device is to be connected to the serial. Terminals and printers use /dev/tty?a style port names with terminals have "login" enabled on the port. Modems require the /dev/tty?A port name so that the hardware flow control wires are available for the modem.


For more details, you need to tell us which type of device that you want to connect.