I'm trying to write a program to interface with a simple device I made (pretty much a RAM chip hooked into a parallel port), and it requires the use of the bidirectional parallel port. I only have a PCMCIA parallel card, and so far, using it for SPP unidirectional transfers, it's fine. Everything works perfectly. However, setting bit 5 of the CR causes all data registers to jump to 0xFF. After reading the documentation, I see that I need to set the ECP Control Registers high three bits to "001", but I can't get access to them. The port's base address is 0xFFE8. I am using Windows XP, but that's not the problem; I'm using WinIO and I can get access to all SPP registers. I've tried writing to port 0x03EA (0xFFE8 + 0x0402), and I've tried reassigning the ports to just about everything under the sun. Nothing seems to work. Anyone know what's going on? It's a Quatech SPP-100.