National Instruments 781473-01 Serial Interface Module 

National Instruments part number 781473-02 is an identifying part number for the PXIe-8431/16, a Serial Interface Module. This device is a 16-port RS485/RS422 module designed for high-speed communication with RS485 and RS422 devices. It features high-performance DMA transfers, multithreading, and multiprocessor support. Users can select between 4-wire and 2-wire transceiver modes for full-duplex and half-duplex communication. Additionally, NI serial interfaces appear as standard COM ports, ensuring compatibility with programs that utilize serial communications. 

The 781473-01 has specific power requirements to operate efficiently. It requires a +12 VDC supply with a typical current draw of 250 mA and a maximum of 280 mA. Additionally, it needs a +3.3 VDC supply with a typical current draw of 1.4 A and a maximum of 3 A. These specifications ensure the module functions correctly within its power limits. 

The I/O connectivity for this device is facilitated by two 68-pin VHDCI connectors. These connectors provide a high-density interface for connecting to various external devices and peripherals, ensuring robust and reliable data transfer. RS422 and RS485 are both standards for serial communication that offer high-speed data transfer and long-distance communication. 

RS422 and RS485 both use differential transmission lines, which help reduce noise and improve data integrity over long distances. RS422 allows for a maximum of 1 driver and up to 10 receivers on the bus, with a driver output voltage ranging from 2 to 6 V and a driver load of 100 Ω. In contrast, RS485 supports up to 32 drivers and 32 receivers, which makes it suitable for more complex networked communication systems. The driver output voltage for RS485 ranges from 1.5 to 6 V, and it has a driver load of 60 Ω.