The NI-6584 is a digital I/O adapter module that, when combined with a PXI FPGA Module for FlexRIO or the Controller for FlexRIO, creates a digital instrument for interfacing with 16 RX and TX pairs of RS485 or RS422. This digital I/O adapter module for FlexRIO can be used to do real-time interfacing and analysis of RS485 and RS422 as well as other electrically compatible interfaces. The NI-6584 can sample digital waveforms at up to 16 MHz clock rates, has terminated and unterminated options, and full and half duplex configurations.