Installing the Plugable USB to RS-232 DB9 Serial Adapter on Windows 7

Windows 7 will detect and pop up a wizard to install drivers when our Plugable USB to Serial adapter is plugged in, but it’s also easy (as essential on other operating systems) to install the driver software first. Here’s how.

Get the driver from:

You’ll want to download the driver and unzip it anywhere on your desktop. Once you have, double click on it to start the installation.

The installation is relatively simple and no questions are asked. When it’s done you should see something like this:

Now go ahead and connect the adapter. You should get a pop-up looking like this:

Finally Windows should report that the device has been installed:

On Device Manager you should be looking at something like this:

14 comments on “Installing the Plugable USB to RS-232 DB9 Serial Adapter on Windows 7”

  1. norman Reply

    Not working at all, prolific 2303, bought two converters, bot of them are not working, no pop ups, prolific is totally crap…
    This should not be this hard…

    • David Roberts Reply

      Hi Norman,

      Because the USB serial adapters work with a wide range of legacy equipment they often require some configuration in order to work. Are you using Plugable adapters? If so, please contact us at I’ll be happy to help with it.

      If you are using another brand, check in device manager for the Ports (COM & LPT) listing shown in the blog post above. If you installed the correct driver, and it’s not showing up there, it is possible your adapters have a counterfeit chip. Prolific has specifically written its drivers to check for a genuine chip and not work if the chip is fake.

      If you are sure the chip is genuine, and its not showing up in Device Manager for both adapters, it’s likely a software issue.

      If it is showing up in Device Manager, but not connecting to your computer, please make sure the COM port shown in Device Manager is set in the software you are using to communicate with your device and that you have the correct type cable (Null Modem or Straight) for your device and that the Port settings are correct.

      I hope this helps,

      Plugable Support

  2. ray-an Reply

    after i install the software there is a pop up saying its not successfully installed.i only follow the instructions above,how do i fix this?thanks a lot

    • David Roberts Reply

      Hi Ajay, Thank you for posting. Are you using the Plugable USB-Serial adapter? If so, please contact us at If it isn’t a Plugable serial adapter, it is difficult to troubleshoot, since many non-Plugable adapters have counterfeit chips in them and don’t work with the Prolific drivers. A few pointers though:
      1. Go to Device Manager > Ports(Serial & LPT) and check which COM port the Prolific serial adapter is using. Make sure that port is set in the software you are using to communicate with your peripheral device.
      2. Make sure you are using the right cable for your application. Some devices, like Cisco routers, only work with the cable supplied by their maker. Other devices require a Null Modem cable, which connects send on each side to Receive on the other side. You can usually find out which to use by consulting the manual for your device.
      3. Make sure the port settings are correct. You can change these by double-clicking the USB-Serial adapter in Device manager, then selecting Port Settings from the Properties window that will open.

      I hope this helps.

      Plugable Support

    • David Roberts Reply

      It depends on the chip in the adapter. For the Plugable PL2303-DB9 USB to RS-232 adapter, drivers are available from our driver page here:

      For other makers, please contact them directly for the drivers that work with their product. Please note that there are many generic USB to RS-232 adapters out there with counterfeit PL2303 chips in them that won’t work with the Windows 8 Prolific drivers for this chip. The drivers now check for a genuine chip and if one is not found, the driver won’t work.

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