USB Blaster won't program via MV interface?

Hi, thanks for your response. No schematic although, I did some reverse engineering yesterday to find out that the interface is not a true JTAG interface even though the connector on the CPLD board is a JTAG connector. The board and the (special) parallel cable have to be used together to program the device. I'll have to modify the boards to program via USB Blaster. I'm a little worried about connecting directly to CPLD JTAG pins because all interfaces I've seen include a buffer in between?