Maybe... The speed is mostly limited by the data transfer via the used bus. Now the ISA clock is 4.77MHz (although the modern PCs which have ISA usually violate it and can go up to PCI/3=11MHz, based on BIOS settings) while the classic PCI clock is 33MHz... One PCI/LPT chip datasheet (NetMos/MosChip NM9805) for example claims...however, in PC, it is not trivial to render the PCI/ISA bus completely for the task you intend (LPT port data transfers only), so you might end up with a lot of troubles to get a regular sample rate consistently, especially under Windows. And, worse, this all changes from PC to PC. Simply put, PC is NOT intended for control applications with defined latency...

An another remark, although it might seem illogical, but the vast majority of onboard LPT ports (contained in combo chips together with serial, FDC and others, called superIO) is NOT connected directly to PCI bus! Some of them are contained directly in chipsets (e.g. SiS chipsets) and are logically tied to an ISA-like bus, for others the ISA bus is produced locally by the southbridge (but usually without being exposed to the user directly on a slot), and the most modern approach is the so called LPC bus (yes, it is an acronym from Low Pin Count, becoming a sort of paradigm these days, isn't it?) which is a stripped-down PCI bus, being clocked as high as the PCI, but multiplexing commands, addresses and data on a 4(!)-bit bus... It has been designed explicitly with slow access in mind.

Jan Waclawek