AMOSi:Open Port

an example can be found on AMOSPro_Examples:Examples/H-6/Help_67.AMOS

Provides a simple way of accessing the various devices connected to your Amiga.

Open Port channel number,"PAR:"

For the Parallel port.

Open Port channel number,"SER:"

For the RS232 (serial) port.

Open Port  channel number,"PRT:"

For the Printer port.

Once you've opened your channel, you can access it using any of the INPUT#,INPUT$,PRINT# or LINE INPUT# commands, just as if it was a normal disc channel.