10.4: Share a serial port with Windows on Parallels

Jan 12, '07 07:30:00AM

Contributed by: brw3sbc

The Problem (as I faced it): I have need to use a serial port to connect my MacBook to my amateur radio equipment. The USB/serial port adapter that I have chosen is the Keyspan USA-19HS. There are both Mac OS and Windows programs applicable to my needs; however, they differ in their purpose, and thus I need the Windows environment to supplement my Mac-based operations.

Initially, I had set my Mac to use Boot Camp to provide the Windows XP environment. This was necessary because the Keyspan driver under Mac OS would not release the serial port adapter to Windows under Parallels, and I did not want to have to remove the drivers from Mac OS each time that I wanted Windows to use the serial port. Rebooting to the other environment was the solution that I came up with; until I read about SerialClient.

The Solution: SerialClient is a Mac application that (in my own words, which may not be technically accurate) takes the serial port away from the Mac OS and links it to Parallels for use by Windows applications running under Parallels. I'll not pretend that I know the intimate details of how this works, but keep reading to learn how to make it work.

After installing SerialClient, launch Parallels and access the configuration editor (under the File menu: Edit Configuration). Note that if you have your Windows Virtual Machine set to AutoStart, you'll need to shut the VM down in order to access the configuration editor.

Select Serial Port in the configuration page's Resource column. If it doesn't appear on the list, use the Add button at the bottom of the window to add a serial port. Proceed to set the parameters as follows:

DEVICE STATUS
Select "enabled" (checked), select "Connect at startup" (checked).

EMULATION
Select "Use socket"; Socket Name: /tmp/serial; Select "Server" in the popup.

You may now start your Virtual Machine.

Connect the USB/serial adapter to your Mac and to the relevant peripheral equipment. This physical connection may occur at any time prior to this point. The Mac OS drivers for the Keyspan must be in place so that the Mac OS and Mac applications (such as SerialClient) can sense and communicate with the adapter.

Back in the Mac OS, run the SerialClient program and set it to the following parameters:

stream path: /tmp/serial
Serial port: USA19xxxxx (select from the serial ports in the drop down menu)

Set other parameters as may be appropriate to the hardware with which you plan to interconnect. For example:

9600-8-N-1 (Hardware RTS/CTS) -- these characteristics are dictated by the outboard equipment with which you are interconnecting.

Finally, click Connect. The button should switch to "Disconnect" and hold.

I suggest that you Save your SerialClient configuration, or else you'll have to re-input it each time you use it. Since I am a frequent user of a particular SerialClient configuration, I have the file represented in my Dock (the file, not the application.)

In Windows, launch the application that will communicate with the equipment. Ensure that the application is addressing the appropriate serial port and that any other associated parameters are correct. Assuming that I've not missed anything nor made an error in the preceding, and that you have also not made an error, you should have the communications that you sought.

Final Note: Thanks to Steve, NI5V for this post, which helped me greatly.

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