NI SMB-2163 Single-ended accessory for NI 6536/7, NI 654x, and NI 655x digital instruments SMB connectors for easy access to data and control signals Rack-mountable design Overview The National Instruments SMB-2163 is a breakout box for NI single-ended high-speed digital instruments to give you direct access to all pins on the device through SMB connectors. Connect to the NI SMB-2163 with the shielded (SHC68-C68-D4) or unshielded (C68-C68-D4) digital cable from NI 6536/7, NI 654x, or NI 655x digital instruments.