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PCI-ICM422-4 and PCI-ICM485-4

Isolated Four-Port Serial Interface Cards


  • This product has been discontinued. Please contact us for help in finding a suitable replacement.
  • Great News! ACCES has designed the PCI Express replacement for this discontinued product. Just a click away to the PCIe-ICM Family!
  • Universal PCI, PCI-X, 3.3V and 5V compatible (Call for PCI-Express availability)
  • Optically isolated,asynchronous serial communications
  • Choice of EIA 422 or EIA 485 models
  • Type 16550 buffered UARTs protect against data loss in multitasking systems
  • Baud rates up to 460,800 baud
  • Usable at cable lengths up to 4000 feet
  • Detected as standard COM ports under Windows
  • No base address or IRQ switches to set
  • Designed, made, supported, and manufactured in the USA
  • Support for Wind River VxWorks (call for ordering information)
These cards can be installed in any 5-volt PCI-bus computer that can accommodate "long" cards and are designed to provide effective communication on long communication lines in noisy environments. The data lines are opto-isolated from the computer and from each other to assure communication even when large common mode noise and voltages are superimposed. Type 16550 UARTs are used. These include a 16-byte transmit/receive FIFO buffer to insure against lost data in multitasking operating systems. All ports are independently addressable and an on-board crystal-controlled oscillator permits precise selection of baud rates up to 115,200 baud or, by changing a jumper, up to 460,800 baud.

Input/Output connections are via a 37-pin D connector on the card mounting bracket. The standard configuration also includes 18-inch long (457 mm) breakout cables for two and four port connections.

EIA 485 models support half-duplex communications with a two-wire cable connection. Also, in EIA 485 communications under Windows programs, the driver must be enabled and disabled as needed to allow multiple communication ports to share the same two-wire cable. The PCI-ICM485-4 card controls the driver automatically. Under this automatic control, the driver is enabled when data are ready to be transmitted and then, when transmission is complete, the driver remains enabled for one additional character's transmission time and then is disabled. Correspondingly, the receiver is always enabled except during transmission time and then re-enabled when transmission is complete.

A transmission line should be terminated in its characteristic impedance at the receiving end. Jumpers are provided for each port to select termination impedances on the lines.

When the card is first installed, Windows will detect it as new hardware and assign it an IRQ number and base address. There are no switches to set or base addresses to assign, making it easy to use. From this point on, the card behaves as standard COM ports starting at COM 5. You cannot set or change the card’s base address, you can only determine what the system has assigned. The PCI Bus supports 64K of I/O address space so your card's address may be located anywhere in the 0000 to FFFF range.

Available Reference Manuals

Available Software Downloads

Drivers and Downloads

Full list of available Downloads: Software Packages, Drivers, Manuals, and other documents

Information about our Free Software packages:

ACCES is proud to provide a full suite of software support with every Data Acquisition product. We are committed to supporting the most popular operating systems and platforms for our customers. Currently we are actively supporting Windows XP through Windows 10, including "Server 2008," "Embedded," and "Compact" flavors in both 32-bit and 64-bit for all plug-and-play products including PCI, PCI Express, USB, and more. Many products continue to ship with support for additional operating systems such as DOS, Windows 95, 98, Me, NT4, and 2000.


Among the software we deliver with our products are sample programs in a wide variety of programming languages. These samples are used to demonstrate the software interfaces to our products — and many can be used as-is in your production environments, or to test functionality of the devices out-of-the-box. We're currently actively supporting sample programs in Visual C# and Delphi with many devices including samples in Visual Basic and Visual C/C++, as well as Borland C/C++ 3.1 for DOS. Additionally we provide National Instruments LabVIEW compatible DLLs and demonstration VIs for many of our devices.


Drivers for various operating systems are also provided, including active support for Windows XP -> 10 — all in both 32-bit and 64-bit flavors, and including consumer, server, and embedded varieties — as well as the Linux kernels 2.6 and newer and recent macOS versions. Many products continue to ship with driver support for Windows 95, 98, Me, NT4, and Windows 2000, but support for these operating systems is considered deprecated.

Setup Programs and Utilites

Our Data Acquisition devices also include a graphical setup utility that walks you through the process of configuring any option jumpers or switches on the device, as well as explaining a little about the various connectors present.

Many devices also include utility programs - little tools to make your use of the device easier, such as WinRISC, a "Really Incredibly Simple Communications" terminal program that lets you get started instantly with serial devices.

"Register Level" Documentation

Besides all this software in all these languages and operating systems ACCES has a policy of open and transparent development: none of our lowest-level "register" interfaces are hidden from you — we document every register in every bus card, every command in every serial board, and every usb control transfer in every USB Data Acquisition board. These lowest-level interfaces allow you to develop for our products in ANY operating system or language, regardless of our actively supporting it or having a driver for it. We have customers actively developing in ADA, Android, Python, Java, MATLAB, Solaris, and more, just by referring to our complete low-level interface documentation! And we provide the full source code to all of our drivers, regardless of operating system, to give you an even bigger head start in your own development tasks.

No Fees or Royalties

All of this software is provided at no additional charge, and is licensed under any of a variety of flexible — and royalty free — options. Check out our software license explanation if you'd like more information.

Custom Software

ACCES also offers Custom Software Services for our products. Our prices are unbelievably low, often as inexpensive as free! If you need something tweaked to support your needs, or an entire enterprise application developed from scratch, it is definitely worth your time to inquire with us, first.

Further information about available ACCES Software:

Redistributing Windows Drivers
A list of ACCES drivers and the files that compose them under different versions of Windows, so you can easily redistribute ACCES cards and drivers.


ACCES has successfully partnered with Wind River to bring our entire line of PCI and PCI Express Serial Communication cards to VxWorks 7! All ACCES plug-and-play serial cards are now supported with our VxWorks driver, including RS232, RS422, RS485 (2- and 4-wire) and baud rates up to 10Mbps.

Designed as an update to the existing vxbPciNs16550Sio.c driver, we've added support for ×8 baud rates, proper handling of the unique register location of the 4th port in the Pericom PI7C9X7954 UART, and configuring the serial protocol from your application software.

With this driver suite all ACCES PCI, PCI Express, PCI Express Mini Card, M.2, PCI-104, PCIe/104, and all related "PCI Style" plug-and-play serial cards will detect and install as standard VxWorks SIO ports.


Communications Interface

  • I/O Connection: 37-pin DBM connector
  • Serial Ports: An external breakout cable that terminates in a female, 9-pin Sub-D connector for each port
  • Character length: 5, 6, 7, or 8 bits.
  • Parity: Even, odd or none.
  • Stop Interval: 1, 1.5, or 2 bits.
  • Serial Data Rates: Up to 115,200 baud, Asynchronous. A faster range of rates, up to 460,800 baud, is achieved by jumper selection on the card. Type 16550 buffered UART is used to assure against data loss in multitasking systems.
  • Address: Each port individually mappable anywhere within the 0000 to FFFF (hex) range of the PCI bus
  • Receiver Sensitivity: ±200 mV, differential input
  • Common Mode Voltage Rejection: Opto-isolation provides 60 volts isolation signal-to-ground and signal-to-signal
  • Transmitter Output Drive Capability: 60 mA, with thermal shutdown.
  • Isolation: 60 VDC


  • Operating Temperature Range: 0o to +60o C
  • Humidity: 5% to 95%, non-condensing.
  • Storage Temperature Range: -50o to +120o C
  • Power Required (four-port cards): +5VDC at 125 mA typical, -12VDC at 5 mA typical, +12VDC at 5 mA typical, 750 mW total power consumption.
  • Size: 12.3" long (312 mm)

Regulatory Compliance

  • This product is in full compliance with CE requirements.

ModelPrice (USD)

Acquisition, Control, Communication: Engineering and Systems