Laptop computers do not have regular PCI slots for add on cards. You can therefore hook this card up to one using either a USB cable, or a Parallel port on the laptop (parallel ports are virtually non existent on newer laptops though).
Hooking up to a desktop computer you can use an internal pci slot, a usb port or the parallel port.
To use on the Acer 5520, you would either have to use a usb cable, or get an ExpressCard parallel adapter. Much simpler to use the usb cable.