Installing a USB Serial Adapter on Mac OS X

The easiest way to go about installing our Plugable USB to Serial adapter is by starting with the device.

  • If you want to verify that the adapter and the driver were installed properly click here

Connect the device to the Mac. Once connected click on the Apple icon and on ‘About This Mac’

Click on ‘More Info…’

Click on ‘USB’ on the left and on the ‘USB-Serial Controller D’
If all is well you should be seeing something like this:

Time to get the driver! Fire up Safari and browse to and scroll down to Mac.
Click on the ‘PL2303 MacOSX10.6 dmg’, the Safari Downloads window should come up:

Double click on the md_PL23-3_MacOSX10

Now double click on the PL2303_1.4.0.dmg to mount the image

Now double click on the PL2303_1.4.0 to start the installation

Once the installer comes up click ‘Continue’ to proceed.

Then ‘Select a Destination’ click on your desired drive and click ‘Continue’ to move forward

Now just click ‘Install’ to continue.

You may be asked of your username and password – enter them and click ‘OK’

You’ll get a warning about restarting the computer after the installation is complete. This is normal, click ‘Continue Installation‘.

Installing should start (takes a couple of minutes to complete)

When it’s done you should see this:

Click on ‘Restart’ to reboot the Mac.

 After you restart, check that everything has installed OK.
On the Mac there are two methods to determine this:

Method 1:
Click on ‘Applications’

Click on ‘Utilities’

Click on ‘Terminal’

kextstat | grep prolific
ioreg -c IOSerialBSDClient | grep usb
Your results should be very close to this:

Method 2:
Click on ‘System Preferences’

Click on ‘Network’

Now click on the ‘+’ sign on the bottom left, and then on the ‘Select the interface and enter a name for the new Service’ click on ‘Interface’ – you should be seeing the ‘USB-Serial Controller D’ there.

This will create a “Network” interface for a modem or serial port. Because it’s a serial port, it’ll say “Not Configured” and that’s normal:

From the “Advanced” button you can change default settings (usually not needed). And this won’t change the “Not Configured” message – that’s still ok.

Now finally, you need an application which will talk to the serial port. On Mac, the file which maps to the port is /dev/cu.usbserial. If you have a null modem cable and a terminal program on the other side, the Mac actually has a built-in terminal program called “screen” that you can use to test the connection.

Once that is up and connected (and if the serial ports are set to the same baud rate and paramters), you can type on either side and see the characters come across.


USB Serial on the Mac is a real melding of the very new and very old. If you have any trouble, just visit to see existing FAQs for Plugable’s USB Serial adapter.

Where to Buy

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88 thoughts on “Installing a USB Serial Adapter on Mac OS X”

  1. Hello,

    Thank you for your comment. We are going to try to reproduce this problem, and if we can, we’ll post our findings here. Also, we would be grateful if anyone experiencing this issue could open a support ticket by sending an email about the problem to Thanks!

    1. Hello David

      I emailed support with a description of the problem. Hopefully they will be able to reproduce the issue and find a resolution.


  2. I have the same problem with me Enttec DMX Pro: My message error is :
    /dev/tty.usbserial-00002014: Permission denied

    Any help ???

    1. Hi Nelson,

      Permission denied errors usually mean you don’t have sufficient permissions to access a device directly. Try accessing /dev/tty.usbserial-00002014 as root through su or sudo.

      Plugable Support

  3. also i have found that attempting to find the right bit rate the screen daemon gets stuck running and will error next time connecting with cannot find PTY – open activity monitor and show all process and find screen and force quit to resolve

  4. Had to boot up an old V240, found my trusty old usbserial cable, only had iMac so googled driver, found this page, have to compliment author on a simple ABC process that works a treat :)

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