Hi,
A GPIB board is a control interface, sort of like the serial port, for communicating with instruments, printers,plotters that have GPIB interfaces as well. It really isn't designed to be used as an direct I/O, but rather a specialized communications port. I was going to say it is like the parallel port, which technically it is, but I had just answered a question on interfacing inputs to the parallel port in another thread. I'm guessing that you have the GPIB board, if not, if you are looking at what interface card to buy there are a lot of possibilities, mostly dependent on your technical requirements and funds available. As I mentioned, it is possible to use the parallel port, and what you are describing might be better served by an external, "controlled" attenuator. It sounds like you want to pass a group of signals through some type of controlled attenuation. I'm not sure, without spending a little more time thinking about it, of anything readily available on the NI site. It also is dependent on the signal levels, frequency, expected attenuation, etc.
Give us a little more info on what you are trying to do,
Putnam Monroe
Certified LabVIEW Developer
Senior Engineer
North Shore Technology, Inc. a National Instruments Alliance member
PutnamCertified LabVIEW Developer
Senior Test Engineer North Shore Technology, Inc.
Currently using LV 2012-LabVIEW 2018, RT8.5
LabVIEW Champion