USB to RS232 Adapter and Driver Advise - Heeeeelllllllpppppp Please!!

My guess is the PL2303 driver is not compatible with Snow Leopard so it never is loaded. That driver is made by a third-party entity who rarely update it.

I've got a client who needed com ports for older Ham gear (one to change the frequency and another for aiming an antenna). Parallels and WinXP works well for him, with multiple USB to Com Port adapters. I think he got the adapters at RadioShack, so they're nothing special.

Bootcamp is overkill for simple Windows needs like this. Parallels will provide all the speed you need for terminal type programs. I see old windows terminal programs required to configure older equipment all the time. I also need to work with some video camera setups that require IE Explorer only (probably activeX issue) to monitor the system. Parallels and WinXP works well here also.

Keyspan has some universal USB to RS-232 adaptors. There may be others. However, they still may not work if the device itself requires that PL2303 driver. I don't think the driver is to make the adaptor work. I have a couple of glucose meters that used that driver along with a USB to RS-232 adaptor that connected to the meter. I had to stop using it because the driver was no longer able to work with Leopard. Whether this is the case for your device I don't know. But that was my experience. I still have the last version I downloaded and the file is dated 6/10/2006 for the OS X PL2303 Universal Binary for 10.4.

Download Sun's VirtualBox, and then snag your favorite linux distro. Make sure you add your usb adapter to the list and you should be fine. Minicom is what I use in a virtual slackware instance and it runs like a champ, and is all free. Hope it helps.

Which PL2303 driver did you use? There are a few floating around. This one at SourceForge.net works perfectly for me under Snow Leopard.

Let's figure out what you have first. Plug in you RS-232 adapter. If the system has a driver that recognizes it, it should pop up a window about detecting a new network interface. If that happens, your USB device is recognized and should be working. If not, you may have the wrong driver loaded.

In any case, open the System Profiler application (click the Apple logo in the menu bar, then About This Mac, then More Info). When the app opens, click USB (under the Hardware heading) in the left window pane. This will reveal all detected USB buses, hubs, and devices. On my system, my RS-232 adapter shows up as USB-Serial Controller. Clicking on it shows these details in the bottom pane:

USB-Serial Controller:

Product ID: 0x4026
Vendor ID: 0x1453
Version: 3.00
Speed: Up to 12 Mb/sec
Manufacturer: Prolific Technology Inc.
Location ID: 0xfd323000
Current Available (mA): 500
Current Required (mA): 100

Your details may be different, especially the Product and Vendor ID. For the PL2303 driver to work, I think the important part is that the Manufacturer is Prolific Technology. If it's something else, you may need a different driver. Try to find your device, and reply back with its details.

With the adapter still connected, click Extensions (under the Software heading) in the left window pane. A list of all kernel extensions will be displayed. This will take a while.

On my system, with the driver that I recommended, the extension name is osx-pl2303. Clicking on it shows these details in the bottom pane:

osx-pl2303:

Version: 1.0.0d1
Last Modified: 05/27/06 11:49
Kind: Universal
Architectures: i386, ppc
64-Bit (Intel): No
Location: /System/Library/Extensions/osx-pl2303.kext
Kext Version: 1.0.0d1
Load Address: 0x3599e000
Valid: Yes
Authentic: Yes
Dependencies: Satisfied

If yours also displays this, then your device should be working. If so, then you'll need to figure out how to get your software to recognize it. Reply back with whatever details you find.

From what I can see perusing some Ubuntu Linux forums, the HL-340 is not a PL2303 device, but rather a CH341 device. That is why you don't see the osx-pl2303 driver in your Extensions list. The extension will only be loaded if a supported device is plugged in.

There does not appear to be a Mac OS X driver available for CH341 devices.

You might be able to get it to work in a virtual machine running Windows or Linux. But it will probably be much easier and cheaper to find an adapter based on the Prolific PL-2303 chip, using this driver. Here's a starting point.

Just buy yourself a Keyspan USA-19H from Tripplite or other supplier.
It works. I had an old adapter on an old iBook that I then tried to
use on a newer machine running 10.6 and it didn't work. I spent a few
days trying to get up-to-date drivers etc. and wasted a lot of time.
Much easier to get something that is known to work, then you can get
back to work and stop wasting time 🙂

Dave

Hello,
I have been working on Mac a driver for this cable, and it works reasonably well for me. I also wrote an app to access the adapter cable, basically a bare bones terminal program for this adapter solely. If your willing to try beta software, check "http://www.staarcom.com/software/"