Using USB to control an LED display

Hey, this is my first post so bere with me as I may be a bit all over the place.

I am trying to control an LED message board via usb. 

It has a manual keyboard on the bottom that upon closer inspection has 8 wires on one side and 7 on the other.
By placing a wire between a wire on one side and a wire on the other a character is inputed.

So by using some sort of USB interface with at least 15 pins I think it must be possible to input to it via USB.

e.g. When A is pressed wires 8 and 15 should be connected in order to input A, for B wires 8 and 14 should be connected, ect.....

I am also getting my Rasberry Pi sonn and was thinking that the GPIO pins could do this but i'm not sure.

This website documents a similar project using the same display but via a different method:

Thanks for reading, please help!!!!