Modules are classified into 13 types:Data Acquisition and Control, Expansion, FPGA, Frame Grabber, GPIB, Serial and Ethernet, IF Transceiver, Interface, Really, Signal Analysers, Sound and Vibration, Switch, Test Support, Timer Counter.Each of these are sub-classified:Data Acquisition and Control: AC LVDT input, Analogue Input, Digital I/O, Analogue Output, Bridge Based Sensor, Bus Power, Electro Mechanical, Multifunction DAQ, Multifunction I/O, Multifunction Synchronous, Multifunction Reconfigurable, Multifunction Temperature and Voltage, Solid-State Relay FET, Sound Vibration Input, Temperature Input, Thermocouple Input, Voltage Input, Voltage Output.Functions are available on NI C Series, Omega DASYLab, PXI, PXIe, and USBExpansion Modules: Analogue Input, CompactRIO, Expansion Bridge, PXI Digital Pattern Instrument, PXI RAID ControllerFPGA Modules: Kintex, Spartan, Virtex, XilinxFrame Grabbers: Frame Grabber Modules, Reconfigurable, PXIGPIB, Serial, & Ethernet Modules: Products for C Series, FlexRIO, GPIB, PXI, MXI and proprietaryIF Transceiver Modules: FlexRIO, PXI and PXI/FlexRIOInterface Modules: C Series, CAN, CANopen, CompactRIO, DeviceNet, FPD-Link, Fieldbus, FlexRay, GMSL, I2C/SPI LIN, PXI, PXI CAN, PXI CANopen, PXI DeviceNet, PXI FlexRay, PXI LINRelay Modules: Electromechanical Relay, PXI, USBSignal Analysers: From Ametek Programmable Power and Digilent, from 92.2Khz to 765MHzSound & Vibration Modules: NI C Series, PXI, PCI, USBSwitch Modules: Electromechanical, Electromechanical Failsafe, Electromechanical Power, FET, Reed, Solid State – on PXI, PXI Express (PXIe), and PXI HybridTest Support Modules: For use with NI CompactDAQ, NI CompactRIO, NI FlexRIO, NI PXI, NI Test Equipment and NI Instrumentation Timer/Counter Modules: For use with NI Compact DAQ, NI CompactRIO, NI DAQ, and NI PXI