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4 Port PCI RS422 RS485 Serial Adapter Card

Add four RS422/485 serial ports to your desktop computer through a PCI expansion slot

Product ID: PCI4S422DB9

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  • Compatible with most major OS platforms including Windows, Linux, UNIX and DOS
  • Easily fits 5 volt and 3.3 volt PCI and PCI-X slots
  • Plug & Play support for Windows O/S environments

This 4 Port PCI RS422 RS485 Serial Adapter Card lets you add four high speed RS422/RS485 Serial interface ports to your system, and features on-card jumpers that let you configure each port as full or half duplex as needed.

The card comes with a breakout style cable that provides four DB9 connectors for use with common RS422/RS485 serial peripherals in virtually any operating environment (point of sale, security, industrial, etc.). The card offers a 32-Byte FIFO buffer and supports data transfer speeds reaching up to 230.4 Kbps.

Intended as a permanent serial solution, the card is backed by’s lifetime warranty and free lifetime technical support.


  • Also used in environments using serial networking devices, high speed modems, monitoring equipment, long distance communication devices and printers
  • Ideal for commercial and industrial applications such as POS networks, ATMs, bank teller stations, and CNC based production lines
  • Factory automation
  • Industrial process control

The Advantage

  • All four ports are configurable to the RS-422 or the RS-485 format
  • Offers data transfer rates of up to 230.4 Kbits/sec per port
  • Designed to avoid conflicts with hardware and software products which makes installation easy and hassle free

Partner Numbers

  • UPC 065030804332


  • Windows 8 logo
  • Linux logo
  • Windows 7 logo
Windows® 8 (32bit), 7 (32) Vista (32/64), XP (32/64), 2000
Windows® Server 2003(32bit)
Linux, Unix SCO Open Server


Warranty Information Warranty Lifetime
Connector(s) 1 - Connector Type(s) PCI / PCI-X (Universal 3.3 & 5V, 32-bit)
4 - External Ports DB-9 (9 pin, D-Sub)
Environmental Operating Temperature 0°C to 55°C (32°F to 131°F)
Storage Temperature 0°C to 65°C (32°F to 149°F)
Humidity 5~85% RH
Hardware Ports 4
Interface Serial
Bus Type PCI / PCI-X (5 / 3.3V)
Card Type Standard Profile
Port Style Dongle (Included)
Industry Standards RS422, RS485
Chipset ID Texas Instruments - TL16C554A
Packaging Information Package Length 8.7 in [22 cm]
Package Width 2.2 in [56 mm]
Package Height 5.9 in [15 cm]
Shipping (Package) Weight 15.5 oz [440 g]
Performance Serial Protocol RS-422/485
Max Baud Rate 230.4 Kbps
Data Bits 5, 6, 7, 8
FIFO 32 Bytes
Parity Even, Odd or No-Parity Bit
Stop Bits 1, 1.5, 2
Supported Protocols Automatic Data Direction Control (ADDC®)
Physical Characteristics Product Length 5.0 in [12.6 cm]
Product Height 4.0 in [10.2 cm]
Software OS Compatibility Windows® 8 (32bit), 7 (32) Vista (32/64), XP (32/64), 2000
Windows® Server 2003(32bit)
Linux, Unix SCO Open Server
Special Notes / Requirements System and Cable Requirements Unused PCI slot
Note One IRQ mapping assigned by PCI BIOS
What's in the Box 1 - Included in Package Serial Card
4 Port DB9 Break-out Cable
Driver CD
Instruction Manual


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Frequently Asked Questions


When you troubleshoot issues with a serial device, there are some quick tests that you can complete to rule out potential problems. You can test to make sure that the following components are working correctly and are not the source of the issue:

  • Serial cables

  • Serial ports

  • Serial devices

To test your setup components, try the following:

  • Use the serial cable, serial port, and serial device in another setup to see if the problem is with the components or the setup.

  • Use a different serial cable, serial port, and serial device in your setup to see if the problem persists. Ideally, you should test a component that you know works in another setup.

When you test your cables, it is recommended that you do the following:

  • Test each cable individually.

  • Use short cables when you are testing.

When you test the serial ports and serial device, it is recommended that you do the following:

  • Press the Windows key + R, type devmgmt.msc, and press Enter to open Device Manager. Check to see if your device is listed under Ports (COM & LPT).

  • Make sure that the COM port number is the correct number for the serial device and that the software being used to connect the computer to the serial device uses the correct COM port number. 

  • If the device is listed with an error, follow the instructions on the website to reinstall the drivers.

Note: Some serial devices work only if the COM port number is between a certain range. For example, COM1 to COM4.

To check whether or not an RS-232 serial port is working, perform an RS-232 loopback test by doing the following:

  1. If your serial port is not female, convert it by taking a female/female cable or gender changer and plugging it into the serial port.
  2. Take a metal paperclip or wire and cross pins 2 and 3. If you look closely at the female end, the pins should be numbered.
  3. Open a telnet session on the COM port number of the device that you are testing. To find out the COM port number, refer to the following FAQ:

Note: To open a telnet session on the COM port, you need a telnet client like PuTTY or Hyper Terminal. Windows XP comes with Hyper Terminal.

  1. When the session is open, anything you type into it you should see. The loopback test fails when you cannot see what you are typing.

If the loopback test fails, make sure that the serial cable or gender changer that you are using works and that the adapter is in the correct port. 

You can check multiple ports at the same time by opening multiple sessions, putting the loopback adapter on one port, and trying to type into each session.  When you can see what you are typing, you know that the COM port is working and you can see which port number the physical serial port is. Close the window for the port that you just tested to speed up the testing of the remaining serial ports.

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How To

To confirm that Windows detects your expansion card, complete the following:

  1. Press the Windows key+R, type devmgmt.msc, and press Enter.
  2. In Device Manager, under the appropriate heading, confirm that your expansion card is listed and that there isn't an exclamation mark next to it.  For example, a USB controller card would be under Universal Serial Bus controllers.

Your expansion card is listed according to the name of the chipset. To determine the name of the chipset of your expansion card, navigate to and look on the Technical Specifications tab for your product.

Compliance and safety

Compliance letters

Safety Measures

  • If product has an exposed circuit board, do not touch the product under power.
  • If Class 1 Laser Product. Laser radiation is present when the system is open.
  • Wiring terminations should not be made with the product and/or electric lines under power.
  • Product installation and/or mounting should be completed by a certified professional as per the local safety and building code guidelines.
  • Cables (including power and charging cables) should be placed and routed to avoid creating electric, tripping or safety hazards.
*Product appearance and specifications are subject to change without notice.

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