Agilent Technologies 82350 PCI GPIB: The 82350 PCI to GPIB interface card read and write calls use one of two modes: Polling - where bytes are transferred to/from the card, one at a time. Polling mode is advantageous for transferring a small number of bytes because the setup overhead is very low but it does requires CPU involvement for each byte transferred. Interrupt - where an entire buffer is transferred to/from the card without CPU involvement. Interrupt mode is advantageous for transferring large buffers because the higher per byte transfer rate more than compensates for the relatively long interrupt setup overhead.