Single port Parallel 34mm ExpressCard.
Using an Oxford PCI-e chipset for design, the Parallel & serial ports have an independet IRQ address, not like USB based Expresscards that share one IRQ with many USB products.What is different between PCI-e base and USB base products?
PCI-e base - it has own IRQ address, and assigned by system, it is standard for Parallel and Serial RS-232/422/485 products. It has also fast transfer speed, as we know one PCI-e slot has 2.5G. Therefore, 2.5 transfer only for one Parallel port.
USB base - for IRQ address, it is under USB port, Parallel port has no own IRQ address. For USB is has 480Mbps, and it also share with few other USB port, therefore, transfer rate will be share.