The code PXI-8423 -4 refers to a **PXI-8423 RS-485 interface module** from National Instruments (NI). Here's a breakdown of the product details and specifications:

**Function:**

* The PXI-8423 is a module designed to add RS-485 communication capabilities to a PXI chassis.
* RS-485 is a multi-drop serial communication protocol that allows multiple devices to connect on a single bus, enabling data exchange between them.

**Specifications:**

* **Number of Ports:** 4 high-speed, differential RS-485 transceivers.
* **Data Rate:** Up to 460.8 kbps (kilobits per second) - This is the maximum achievable data transfer rate under ideal conditions. Cable capacitance and other factors can affect real-world performance.
* **Isolation:** The PXI-8423 offers optional **galvanic isolation** between the RS-485 bus and the PXI chassis. This helps to protect against ground loops and noise that can disrupt communication. The "-4" in the code might indicate a non-isolated version (verify with the datasheet).
* **Software Support:** The PXI-8423 is compatible with NI software tools like NI-Serial and LabVIEW for programming communication interfaces.

**Finding More Information:**

Obtaining the official datasheet for the PXI-8423 is crucial for precise details and specifications. Here are some ways to find it:

1. **National Instruments Website:**
   * Visit the National Instruments website: [https://www.ni.com/en.html](https://www.ni.com/en.html)
    * Search for "PXI-8423" to access the product page with datasheets, manuals, and other resources.

2. **Download Center:**
    * Look for the "Download Center" section on the product page. There you should find the downloadable datasheet (user manual) for the PXI-8423.

**Additional Notes:**

* The "-4" at the end of the code (PXI-8423 -4) might indicate a non-isolated version of the module. However, to confirm this,  refer to the datasheet or consult NI support.
* National Instruments might offer other RS-485 interface modules with different features or port configurations. Consider exploring their product offerings if the PXI-8423 doesn't meet your specific needs.