There are really three different styles of NI-488 calls: board-level, device-level, and 488.2 style(also known as multi-device).
Board-level calls can be used to do low level GPIB communication. Using these calls typically requires a bit more knowledge of GPIB. When using these calls, you can think that you're talking directly to the GPIB board(or box in the case of the GPIB-USB-B).
Device-level calls are typically used to communicate with a single device on GPIB. When using these calls, you can think that you're talking directly to the device that you're connected to over GPIB. These calls abstract away some of the low level GPIB details so that you can just worry about the messages that you need to send and receive from the device.
488.2
Style, or multi-device calls actually have some board-level and some device-level functionality. These calls were introduced to complement the IEEE-488.2 specification which specifies these routines. There is some overlap in functionality between these calls and the other calls. The 488.2 style calls add the ability to send data to multiple listeners on the bus simultaneously, which you could do with board-level calls if you know how to properly address the devices manually.
Which style calls you select is sometimes a matter of personal preference. It is reccomended that you do not mix 488.2 style calls with the Board or Device level calls. It is ok to mix board and device level calls.
Hope this helps.
Craig A.
National Instruments Engineer
