Do you have communication software? you can send a .txt file with many comunication softwares.
Do you have a cable? You can use a 9 pin to 25 pin, or usb adapters are available.
I set mine up once to dnc from a PC, when my flash-card reader wasnt working, but I went back to the flash card as soon as it was fixed.
You will also need to change a setting in the control, IIRC it is a channel setting so that the control know you are using the comm port.