For decades we’ve relied on our laptop’s trusty Serial Port or PCMCIA Slot to communicate with legacy A-B devices.

But when our old laptop dies, or a new one arrives, it’s very unlikely to have either a Serial Port or PCMCIA slot.

The good news is most all legacy A-B networks can be connected to with the use of USB cable.

But while USB to Serial cables are affordable, the USB cables that replace the legacy PCMCIA cards are just as expensive as the cable they replace.

So whether you need to communicate via RS-232, DH-485, DF1, DH+, DeviceNet, ControlNet, or to a legacy A-B PLC, VFD, or HMI, you should find a USB cable that can do just that in today’s article:


This summer Rockwell released three new USB cables:


Provides a quick and easy connection directly to a controller’s 9 Pin D-Shell serial port via USB, supports RSLinx’s Auto-Configure feature, and eliminates the need for the 9300-USBS and 1747-CP3/1756-CP3 cable combination.

Comes in high visibility orange and includes “null modem adapter” for use with DCE devices like most PanelView terminals.


Provides a quick and easy connection directly to a controller’s 8 Pin Mini-Din serial port via USB, and supports RSLinx’s Auto-Configure feature.

Comes in high visibility orange and eliminates the need to use a 9300-USBS and 1761-CBL-PM02.

NOTE: Rockwell’s original documentation stated this cable also worked with some PanelView Plus models however NO PVPlus models have a 8 Pin Mini Din port.


This cable is for directly connecting to a Cisco or Stratix switch from a USB port.

It essentially replaces the need to carry a Cisco Console cable and USB to Serial converter.


ANC-120e: USB to Data Highway Plus, a lower cost alternative to the U2DHP

In late 2016 I had the good fortune to test the much lower cost ANC-120e USB to Data Highway Plus cable and you can find all the details using the below link:

USB to Serial: 9300-USBS

USB Cables for Serial Devices - 9300-USBSEven though new laptops don’t have a nine pin serial port, most of us still have many devices in the field with them, so this cable is one of the first you’ll want to consider buying.

Rockwell makes the 9300-USBS, which is currently at rev 3 (aka series C) and is fully tested with all A-B products and serial cables.

It’s also one of the few USB serial cables on the market which also supports RSLinx Classic’s “auto configure” option for finding the baud rate of the serial device connected.

However, with a list price of $144, that may be a feature you’re willing to give up.

In the past I’ve purchased USB to serial converter devices which looked identical to the 9300-USBS for one tenth the price and they’ve worked well except for the lack of support of “auto configure.”

If you do buy a third party USB to serial cable I recommend keeping the receipt and testing it right away as you don’t want to find out it’s not compatible when you need it the most.

Low Cost Ttripp lite usbshird Party 9300-USBS:

If you’re looking for a third party USBS which works great and also does support RSLinx’s auto config look no further that this unit which I’ve personally tested and found works like a charm:

USB to DH-485: 1747-UICC13

USB Cable for DH-485 - 1747-UICIf you need to connect to a SLC-500, SLC-5/01, or SLC-5/02, you’ve likely used the large and unwieldy 1747-PIC in the past.

The good news is its replacement is considerably smaller, and supports DH-485 via RS-232 and RS-485.

However, with a list price of $417.00, and only native support for 19.2K (9600 support can be added with a firmware patch from Rockwell found here) it’s not the biggest bang for your cables bucks.

You also need to be careful not to plug in just any Ethernet patch cord to the RJ-45 – it’s a known issue that using an Ethernet cross over cable to connect from the 1747-UIC to a SLC-500 will permanently damage this cable.

This is why I’m recommending the bundle here, the 1747-UICC13: It contains the 1747-UIC and the properly wired 1747-C13 cable.

Low Cost Third Party 1747-UIC:

1747-UIC BlackMany of my clients have forgone the official Allen-Bradley DH-485 USB cable, and instead have used a third party 1747-UIC cable which has the RJ45 and 9 Pin D Shell cables attached, and costs a fraction of the price.

If you’re interested in this third party cable you can find it on Amazon using the link provided below:

USB to DH Plus (DH+): 1784-U2DHP

USB Cable Data Highway Plus - 1784-U2DHPThe U2DHP is a replacement for both the PCMK and PM05 / 06 cables (1784-PCMK, PCMC, PCM5, PCM6) as well as for the many iterations of the KT card (1784-KT, KTX, PKTX, PKTXD) when used in programming stations or PC’s.

It makes connecting to Data Highway Plus via USB possible, although it only has the 8 pin circular mini din connector found on the SLC-5/04 and New Platform PLC-5’s.

At the time this article was written, this cable listed for $2780, making it strictly for the “have to have” crowd.

USB Cable - GracePort C-ABDH-AdapterNOTE: If you need to connect to a Classic PLC-5, or any Data Highway Plus product with a 9 Pin D Shell, you’ll need a separate adapter to convert the 8 Pin Mini Din.

Grace Engineering makes one such device, PN# C-ABDH-Adapter, which you can find detailed on their website using the link below:

Update 10-27-23: Thanks to one of our readers (Peter) for posting an updated link for this item in the comments:

Update 08-10-15: The below link is dead so if you have found another source for this adapter please let us know!

USB to DeviceNet (DNET): 1784-U2DN

USB Cable for DeviceNet - 1784-U2DNThe 1784-U2DN is a replacement for the 1784-PCD and 1770-KFD, and allows for connecting to DeviceNet via USB.

Support for this hardware begins with RSLinx 2.51 and RSNetworx for DeviceNet version 8.

At the time this article was written, the 1784-U2DN listed for $1,610.

USB to ControlNet (CNET) 1784-U2CN

USB Cable for ControlNet -1784-U2CNThe 1784-U2CN is a replacement for the 1784-PCC PCMCIA card, and comes with a ControlNet NAP (RJ-45) connection.

At the time this article was written, the U2CN listed for $1,930.00

USB to A-B Drives / VFD: 1203-USB

USB Cable for A-B Drives - 1203-USBThe 1203-USB cable is as universal as a programming cable as they come, as it supports Scanport, DSI, and DPI A-B Drives.

This includes, but is not limited to, the 1305, 1336 Classic, 1336 Plus, Plus II, Force, Impact, PowerFlex 4, 4m, 40, 40p 400, 70, 700, and 520 series.

It comes with the device itself, a USB cable, a 20-HIM-H10 cable, and 22-HIM-H10 cable.

At the time this article was written, it listed for $358.00

Update: Additional Low Cost Third Party Cables

1761-CBL-PM02Last time I purchased a 1761-CBL-PM02 the price was a whopping $76!

In my search for a lower cost cable, I came across this one which I’ve personally tested and appears to work just as well as the official PM02 cable:

Hopefully you found this listing of A-B USB cables helpful.

If you have any experience with these cables that you’d like to share please do so by using the “post a comment or question” link below.

Until next time, Peace ✌️ 

Shawn M Tierney
Technology Enthusiast & Content Creator

Have a question? Join my community of automation professionals and take part in the discussion! You'll also find my PLC, HMI, and SCADA courses at

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Shawn Tierney



    • Good morning PLC Training,

      While this article is about USB cables used to attach your PC directly to your A-B PLC, we have also covered bridging DH+ to Ethernet in other articles.

      And you are correct that there are used DHRIO cards out there currently ranging in price from $99 – $500, so if someone already has a 1756 rack, ps, and Ethernet module, they can simply add a DHRIO module to complete the “gateway.”

      Of course, that’s just one of many types of network bridges available for PLCs 😉

      Note: For anyone interested in supporting our website I’ve posted our EBay 1756-DHRIO affiliate link below:


      Shawn Tierney

      Join my free community to follow along! You can also become a member and support our work at:

  1. When replacing the DeviceNet Connector some money can be saved by using the 5 pin connector instead of buying the 10 pin that the USB-to-DeviceNet Convertor originally came with.

    The 5 pin DeviceNet connector (1799-DNETCON & 1799-DNETSCON) is available for $15 on the web
    The 10 pin DeviceNet Connector (1787-PLUG10R) is listed on the web for $143.00! ouch.

    • I’ve found the 9300-USBS communicated with everything A-B made (except the 1747-PIC which doesn’t work with USB converters.)

      That said, I suggest (1) trying what you have already, or (2) picking up the inexpensive converter I also use – – before (3) investing in the expensive 9300-USBS (or current replacement)

      Best of luck,


  2. Hi,

    Where can i get the ‘Allen Bradley 1203 usb’? i only see them for $2000 – $4000 on ebay and i can’t afford to pay that.


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