CONV232/485 and CONV232/422

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  • Balanced-mode, long-distance RS-485 and RS-422 communication with no internal installation
  • External power not needed for small networks
  • Nothing to configure; automatically detects baud rate and format
  • Designed, made, supported, and manufactured in the USA
Last updated on November 2, 2023, 6:28 pm


In Stock


The CONV232/485 and CONV232/422 convert between RS-232 communications (as used by the COM1 and COM2 ports standard on most motherboards) and balanced-mode, long distance RS-485 and RS-422 communications.

The CONV232/485 was designed for use with our REMOTE ACCES line when there is no RS-485 port on your PC, but may also be used in other, similar applications.  CONV232/485 supports two-wire RS-485 communications, which is half-duplex (only one may transmit at a time) but allows up to 32 participants on a “party line” network.

The CONV232/422 supports four-wire RS-485 and RS-422 communications, which only allows two peer participants (or one master and multiple slaves) but is full-duplex (both peers, or the master and one slave, may talk at the same time). CONV232/422 can also support two-wire RS-485 if the transmit and receive pins are tied together, but in this configuration it echoes on the RS-232 side.

Internally, TD and RD are converted to balanced lines and the RD line is automatically disabled when data is being transmitted to the RS-485 network. The converters can transmit and receive transparently at whatever speed the data is flowing, up to 460K baud for the CONV232/485 and 230K baud for the CONV232/422. CONV232/485 (and CONV232/422 in a two-wire RS-485 configuration) can support up to 31 other RS-485 devices (with the optional external power). CONV232/422 in a master-slave configuration can support up to 31 slave devices.

The converters plug into your RS-232 port, and all you need to do is hook up the RS-485 wires via a DB9 Male connector. Optional external power is required when communicating with more than two REMOTE ACCES Pods, or over long transmission lines; if external power is not provided, power drawn from the DTR and RTS lines on the RS-232 port is sufficient where the communication cable is short and there are few nodes.


Data Sheets

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 XP -> 10, both 32 & 64 bit, including “Server 2008,” “Embedded,” and “Compact” flavors 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 Microsoft Visual C#, Visual Basic, Delphi, and Visual C/C++, with many devices including samples in Borland C/C++ 3.1 for DOS. Additionally we provide National Instruments LabVIEW compatible DLLs and many demonstration VIs for 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 2.6 and newer Linux kernels and recent OSX / 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 EWriter, a program that allows you to read and write data in the user-accessible EEPROM locations on all our USB data acquisitition products; or 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.



  • Optional External Power: When communicating with more than two REMOTE ACCES Pods or over long transmission lines, connect +5.5VDC to +16VDC @ 50 mA to J2 pin 8 with return via J2 pin 5.
  • Data rate: Up to 460.8K baud.
  • Serial format: any.
  • Configurations: RS-232 to two-wire RS-485.
  • Operating Temperature: 0-70°C, added-cost option, -40 to +85°C. Add -XT to part number.


  • Optional External Power: When communicating with more than two REMOTE ACCES Pods or over long transmission lines, connect +5.5VDC to +16VDC @ 40 mA to J2 pin 8 with return via J2 pin 5.
  • Data rate: Up to 230.4K baud.
  • Serial format: any.
  • Configurations: RS-232 to four-wire RS-485 / RS-422, RS-232 to two-wire RS-485 (with echo on the RS-232 side).
  • Operating Temperature: 0-70°C, added-cost option, -40 to +85°C. Add -XT to part number.

Regulatory Compliance

  • This product is in full compliance with CE requirements.
ModelDescriptionPrice (USD)

RS232 to RS485 Serial Data Converter


RS232 to RS422 Serial Data Converter