In general, I recommend the ni.com knowledgebase: "Where Can I Find Modules for PXI and CompactPCI?" as a roadmap for finding PXI/CompactPCI modules. It can be found by simply searching ni.com for "third party PXI" or "PXI modules", etc. However, I've searched for one of these before and may have some short-cuts for you.
Most manufacturers of PXI and CompactPCI hardware (NI included) place a single IEEE 1284 port on their system controllers. So selection of certain system controllers (ie NI PXI-8176) will give you one port.
The only hint of a CompactPCI parallel adapter card I found was from www.interface-co.com. Unfortunately, their website looks down, so you might want to shoot them an email at support@interface-co.com to see if they truly do ha
ve one released.
Another way to go is to use USB-to-parallel converters. I've never personally used one, but a search of www.google.com for "usb parallel" turns up quite a few. Using these, you could use the USB port in the PXI system controller to a USB hub, or buy USB expansion CompactPCI cards from www.ekf.de for more USB slots. I don't know if the translation from your parallel device to USB would cause problems or not - might be worth buying 1 USB-to-parallel adapter cable (approx $40) and test it with your devices on a desktop PC before specifying this for the entire system.
One final thought - I would start thinking about transitioning away from parallel port devices if possible. My perception is that this is a nearly-dead standard for communication to both commercial devices (printers etc) as well as instrument or measurement control. In surveys I've seen of instrument control buses in recent years, parallel is no longer even listed as a category next to USB, FireWir
e, GPIB, and ethernet. Also, some people use parallel ports as an extremely low-cost way of doing simple digital I/O. If that is the case, I would recommend a low-cost digital I/O module instead.
Regards,
Greg Caesar
