in PL2303

OSX Installer to PL2303 Serial-USB on OSX Lion / Mountain Lion / Mavericks / Yosemite

Update 1: As some folks said in the comments area: in Mountain Lion (10.8.x), the tool also works!

Update 2: Again, thanks to users those reported that the driver works under Mavericks (10.9.x)

Update 3: Tested over Yosemite Beta (10.10.x) and works perfectly :). Screenshots updated.

Update 4: Some users reporting issues with Yosemite’s latest stable and the origin is a new feature of them called kext signing. Please read more here.

Thanks to ./martijn we have a functional driver to PL2303 chip based devices (to enable a serial port over usb) in OSX 10.7.  To install, you have to do some tasks in the Terminal app, nothing hard. But if you need to do this many times,  it can be boring.

To fix this, I built a native installer that does all the dirty work in a single step, Yayyyyy!!

After completing the process, you can check if everything went well (connect now the usb cable) with the following command:

kextstat -b nl.bjaelectronics.driver.PL2303
with an output like this:

The installer is included below, please check the md5 hash (PL2303 Serial-USB on OSX Lion.pkg) = d6e1a52f2fdbde55bab716037c9630f7

If this tool was useful, please consider donate something! 

Write a Comment




  1. Thank you so much for writing this script, I’m not at all a programmer and this helped me get my ageing Wacom up and running. All the best.

  2. funcion?? perfectamente. Ahora engo operativa la interfase para comunicar sin problemas mi IC7000 y el FT857D.Gran trabajo, much??simas gracias

  3. Hi, I have tried to install it on my Mac Book Pro with OS X, ver. 10.6.8. When the installation starts, on the second screen ask : How do you want to install this software, and the option given there to select (install it on all users…..) is greyed and therefore there is no way to continue with the installation.Can you please help?I am trying to put to work my old Wacom Tablet.Thanks and Regards,Ernesto

  4. THANK YOU VERY MUCH!!!<div>I am new on Mac??s so I am strugling with this. I downloaded??PL2303 USB to Serial Driver for Mac OS X by b_j_arnoldus and finally the latest file was??osx-pl2303-0.3.1-10.4-universal.dmg.</div><div> I did the installation OK. Thank you!</div><div>Now I have connected the Wacom tablet using a software called TabletMagic but the Wacom does not see the Mac yet. I will try to find a user of this config.</div><div>Thank??you??again!</div> <div>Regards,</div><div>Ernesto<br><br></div>

  5. Tried using the installer. My Bushnell Neo connects, but, it flashes on and off between "searching for device" can you help? thanks

  6. Hola!Nada, no consigo que me funcione el driver de ninguna manera. He probado a instalarlo y parece que la instalaci??n se hace, pero mi programa de radio sigue sin mostrarme el puerto serieTengo un Mac Pro con Lion y el programa de radio que utilizo es el McLoggerAlguna sugerencia?Gracias de antemanoArturo

  7. Thanks! Only until I found your Installer I was able to read waypoints from old eTrex Vista in my Mac using a Sitecom CN-116 Serial to USB Converter plus LoadMyTracks, new life for my eTrex Vista. Yayyyyy!!Thanks!!!!!Alberto.

  8. Arturo, lo ??nico que se me ocurre es que tu adaptador no este usando el chipset de Prolific 2303. Conecta el cable y mira dentro de la lista de hardware (en Acerca de este mac) que informaci??n muestra de los elementos conectados a los puertos USB. Saludos!

  9. ChanGux,Muchas gracias. El chipset si es el Prolific 2303. Ya me funciona. Ocurr??a que primero intent?? instalar el driver manualmente sin resultado (no soy muy ducho con el terminal y sus comandos) y luego lo instal?? con tu programa. Lo he solucionado borrando el osx-ol2303.kext del directorio y volviendo a instalarlo con tu aplicaci??n. Ahora funciona perfectamente.Much??simas gracias!Un abrazo,Arturo

  10. Hi,I’m trying to use this driver but don’t work for me.After complete the installation I type the command (kextstat -b nl.bjaelectronics.driver.PL2303) and it’s all right, nl.bjaelectronics.driver.PL2303 (1.0.0d1) <102 30 5 4 3> is there. But when I connect the adapter USB x Serial I don’t have a port in /devPlease help me.

  11. You Rock!!!! Thanks so much I have about 30 Etrex that I use for youth programs and no way to connect them until now!!!

  12. THANKS!!!!!! I’ve been trying to get my iMac to program my Amateur Radio without success because of Lion’s inability to communicate through the USB to Serial adapter. It is now fixed and I’m able to program my Kenwood TH-F6A.

  13. Thank you for this little Gem. I’ve been trying to get my Imac to talk to my ham radio equipment via a usb/serial lead, and thanks to you all works now just fine!

  14. Hola.He observado despu??s de instalar el software que mi ipad y mi iphone no pueden actualizar el firmware con el iTunes. Lo mismo me ocurre con la c??mara de video GoPro, que chequea y actualiza nuevas versiones de firmare a trav??s del software de edici??n de video de la c??mara. Si conecto esos tres dispositivos al Macbook, s?? que permite la actualizaci??n del firmware.??Alguna sugerencia? ??Hab??as comprobado este asunto?Un saludo,Arturo

  15. Thank you for the Installer. Everything seems to work with a loopback connector, but apparently there is a thing with the speed or the format. I have to connect to a device at 9600, 8N1 and all the data comes back scrambled. I am using a Mac Pro with Lion and I ve tried every speed setting but it does??t work with either.

  16. I ran your script and it said it completed successfullyI issued the command go test the install and got some text back that looked like your example but I don’t understand how OSX or Linux/unix works so maybe what I saw said it didn’t workI am trying to program a BaoFeng UV-5R radio using the CHIRP softwareNormally the first thing you do is tell the software what radio you are working on and what COMM port the Ub dongle is plugged intoAs soon as I turn my radio on it goes into transmit modeI can successfully program the radio with this dongle and software on an old Windows XP machine so it seems to be a driver problemWe know that the Chinese have been installing bogus Prolific chips in some of these dongles and that Prolific has released a new driver that is poisoned so that it will not work with the bogus chipsThis is a big problem for Windows 7 users because after you install an old driver that works the OS finds the newer poisoned driver and performs an update without asking if you want to do it or telling you that it has been doneIs the driver your script is installing the latest (poisoned) driverIf so is there a way that I can use it to install an older driver instead

  17. Im glad to confirm that your Package works on a Retina MacBook Pro with Mountain Lion 10.8 like a charm.Although being showed as some kind of generic device in the System listing the tty device is available and works perfect!Thanks alot! You eased alot of pain tinkering with that legacy crap :)

  18. Hi,the installation seems ok and kextstat shows the driver running. What I actually miss is a (dev/tty.*) device entry I could use for Jdatalog (to read from some older GPS logger).Any idea?Thanks,Frank

  19. thanks so much for making this available. worked perfectly on iMac/10.8immediately after install /dev/tty.PL2303-000013FA was working and i could connect

  20. I’ve been struggling with getting my usb serial adapter working for longer than I’d like to admit. Thank you so much! Mountain Lion 10.8.2 confirmed good! :)

  21. I’ve installed the driver on Mountain Lion and it seems to partially work:# kextstat -b nl.bjaelectronics.driver.PL2303Index Refs Address Size Wired Name (Version) <Linked Against> 124 0 0xffffff7f81e9b000 0xb000 0xb000 nl.bjaelectronics.driver.PL2303 (1.0.0d1) <112 33 5 4 3>However, I don’t see any new tty devices added to /dev/tty. Is there another step I need to perform for that?Also – the driver doesn’t seem to load after I reboot my computer. I have had to re-install the .pkg after a reboot, to get the command above (kextstat) to complete correctly.

  22. OS X 10.8.2 Working great with the cable.Thank you for taking the time.Buy you a pint if you’re ever in London.

  23. Bryan,Do you sure that your adapter has the PL2303 Chipset? Please check the logs (with the console utility app) and check for detailed information.

  24. This works great with a StarTech ICUSB232DB25 device. Thanks! It doesn’t seem to work with a Gigaware USB-Serial that was purchased at RadioShack in the US, even though it claims to have a PL2303 as well, and I can see the right ids in the .plist file.Any clues if that device can be made to work on Mountain Lion via this driver or another?

  25. I tried it on OS 10.8.3 and doesn’t. I ran the installer , click done after completed.
    ls /dev/cu* doesnot show the usbtoserial port.

    • Hi. You sure that you usb to serial cable has the PL2303 chipset? If the answer is yes, the driver should work and create a virtual device /dev/cu.PL2303-xxx or /dev/tty.PL2303-xxx

  26. Thank you! You have extended the usefulness of my Serial-USB “Sabrent” cable on my MacBook Retina running OS X 10.8.5

  27. i have mac os x 10.8.5 and i got this usb serial adapter from the problem is I can’t get this thing to work with any driver. it installs but doesn’t show up in hardware usb when I plug it in and i don’t have it under network. i have all security items changed and I even attempted to do the terminal installation which went well but it still doesn’t show up.

    what other chipset could I have.
    Item on the is A108

    thanks for your help and great installer package! keep up the great work it helps us all 😉

    • Hi Neo,
      Are you sure that the serial adapter has the PL2303 chipset? Remember that the driver only works on this. Regards!

  28. I just upgraded to Yosemite from Mavericks and tried your procedure. It is not working for me. I do see the virtual devices in /dev though:

    $ls -l|grep PL
    crw-rw-rw- 1 root wheel 17, 5 20 Oct 15:09 cu.PL2303-00002014
    crw-rw-rw- 1 root wheel 17, 4 20 Oct 15:09 tty.PL2303-00002014

    But I get no response from SecureCRT on selected serial connection

  29. Update: After a reboot I was able to serial into a Cisco device. However, I then disconnect, move the USB serial cable to the other USB port on my rMBP and try connect from there. Fail. And back again, fail. Reboot again and the same thing happens. Able to use serial cable just 1 time. Have to reboot to fix, but then again I just get one shot at it :(

  30. Found this in console when trying to connect:

    2014-10-20 3:38:04.000 PM kernel[0]: nl_bjaelectronics_driver_PL2303(0xffffff804b194400)::allocateResources failed – no fpInterface.
    2014-10-20 3:38:04.000 PM kernel[0]: nl_bjaelectronics_driver_PL2303(0xffffff804b194400)::start Allocate resources failed
    2014-10-20 3:38:04.000 PM kernel[0]: nl_bjaelectronics_driver_PL2303(0xffffff804b194400)::CheckSerialState – StartSerial failed
    2014-10-20 3:38:12.000 PM kernel[0]: nl_bjaelectronics_driver_PL2303(0xffffff804b194400)::enqueueDataGated fTerminate set
    2014-10-20 3:38:12.000 PM kernel[0]: ttyioss1100000d: enqueueData rtn (e00002d7)
    2014-10-20 3:38:14.000 PM kernel[0]: nl_bjaelectronics_driver_PL2303(0xffffff804b194400)::enqueueDataGated fTerminate set
    2014-10-20 3:38:14.000 PM kernel[0]: ttyioss1100000d: enqueueData rtn (e00002d7)
    2014-10-20 3:38:16.000 PM kernel[0]: nl_bjaelectronics_driver_PL2303(0xffffff804b194400)::enqueueDataGated fTerminate set
    2014-10-20 3:38:16.000 PM kernel[0]: ttyioss1100000d: enqueueData rtn (e00002d7)

  31. This is when I insert the USB Serial cable:
    2014-10-20 3:48:54.000 PM kernel[0]: USBF: 1993.724 IOUSBCompositeDriver::ConfigureDevice Could not open device (USB-Serial Controller)

          • It turns out this is an issue with Yosemite not allowing unsigned kernel extensions.(syslog.log –[556]: .kext has invalid signature; omitting.)
            Turning off kext-signing seems to have solved this issue…but not really.
            After disabling kext-siging, I can get the serial connection to work without issue. The problem now is, when I unplug the usb to serial adaptor, my machine hard crashes without so much as a single line in the crash logs.


  32. Downgrade to Mavericks complete, and my serial function is now working as expected. Maybe a virgin Yosemite install works with your driver, maybe mine is muddied up from before. Hopefully it gets sorted out soon.

    • I was getting the same errors as Ed: kernel[0]: nl_bjaelectronics_driver_PL2303(0xffffff804b194400)::allocateResources failed – no fpInterface. when I tried the install on my 10.10 box.

      I managed to fix it as follows.
      1. Removed osx-pl2303.kext/ from /System/Library/Extensions/
      2. Removed the Network Interface “USB Serial Controller – D” from Network Preferences.
      3. Connected my usb serial dongle.
      4. Ran the PL2303_Serial-USB_on_OSX_Lion.pkg downloaded from this site and waited for the install to finish.
      5. as root (or via sudo), ran kextcache -f -system-caches -u /Volumes/Macintosh HD/
      (Last argument is the path to the root volume on the Mac. Adjust as required).

      Now it works fine. In previous attempts after step 4 I could connect to the device but got nothing and syslog showed me errors such as the above and also errors of “could not open USB Serial Controller – D”

      I use screen to connect with it, i.e. screen /dev/tty.PL2303-000013FA

      I hope this may help if you are having the same problem with 10.10.

  33. I have two different serial cables
    Diablo Cable USB–>RJ45
    I had them both working on 10.9.5 until today

    Lots of time wasted trying to make them work.
    Different version of PL2303 drivers.
    Gave up on 10.9.5 and installed 10.10 (still did not work).

    Used your program and both cables work now.
    USB->Serial is so easy on a PC.
    Why is it such a pain on the MAC.


  34. I’m not sure that the kext signing is the issue. I upgraded from Mavericks to Yosemite and my PL2303 adapter stopped working. I tried disabling the signed kext checking just to see, and my adapter still didn’t work. Interestingly, I’ve discovered that if I (re)boot my mac with the adapter already connected, it will work. If I subsequently unplug it and plug it back in, it doesn’t work any more.

  35. I’m in the same boat with Ed:
    08/11/14 17:54:24.000 kernel[0]: nl_bjaelectronics_driver_PL2303(0xffffff804f21bc00)::allocateResources failed – no fpInterface.
    08/11/14 17:54:24.000 kernel[0]: nl_bjaelectronics_driver_PL2303(0xffffff804f21bc00)::start Allocate resources failed
    08/11/14 17:54:24.000 kernel[0]: nl_bjaelectronics_driver_PL2303(0xffffff804f21bc00)::CheckSerialState – StartSerial failed

    I’m on Yosemite and it worked fine in Mavericks before. My cable is a somewhat ancient UC232A. As downgrading is not an option, I’ll wait it out. If I can provide more info to help fixing it, let me know.

  36. Thanks for your work on this. I’ve used the ATEN (PL2303) on mac for ages and it was a real pain to get it working, and then nothing I tried worked once I installed Yosemite.

    Your Paypal account cannot accept funds. Sort that out and I’ll make a donation because this really makes my work life easier.

  37. So there is a little bit of a bug in Yosemite.

    If I disconnect the USB at all, it won’t connect again (if it’s the same USB, the application doesn’t complain, but you get no output. Different USB shows as disconnected).

    If you reboot it works fine.

    If you leave the usb connected and sleep it works fine.

  38. Many thanks for making this available, it is greatly appreciated.

    I have just purchased the console cable from AdaFruit and connected it to a ModelB+. I am running a Mac with Yosemite (10.10.1) and have installed the Serial USB software but unfortunately there is a problem connecting to the Raspberry PI

    I get a message back “Sorry, could not find a PTY”. Just wondering if you had any thoughts on what might be going wrong?

    Kind Regards