National Instruments 779987-01 C Series Digital Module 

National Instruments part number 779987-01 is an identifying part number for the NI-9402 a C Series Digital Module with 4 Bidirectional Digital Channels and 3.3V TTL Digital I/O Logic Level. The NI 779987-01 is a Digital Module designed for plug-and-play ease with USB connectivity for sensor and electrical measurements on the benchtop, in the field, and on production lines. This module integrates signal conditioning and data protection into a compact unit for various measurement types. This device comes with two types of signals for each channel: GND for ground connection and DIO for digital input/output connection. 

The DIO pins allow users to connect digital devices to the 779987-01 module using a 50 Ω BNC cable. Each DIO channel can be configured in software as either input or output and changing the direction of one channel does not affect the others. When used with CompactRIO, the NI 779987-01 module supports both sinking and sourcing input and output configurations. It can be programmed using the LabVIEW FPGA Module to perform tasks like pulse generation, high-speed counters/timers, digital communication protocols, and other customizable functions. 

The NI 779987-01 module defaults to an input direction upon power-on, supporting both input and output operations. It operates with LVTTL (Low Voltage Transistor-Transistor Logic) single-ended signals, suitable for a variety of digital signal applications. The module offers a maximum switching frequency of 16 MHz for 4 channels and up to 20 MHz for 2 channels, facilitating rapid data transmission. With an I/O propagation delay ranging from a maximum of 55 ns to a typical 18 ns, it ensures efficient and responsive signal processing in applications requiring precise timing and synchronization.