This document describes how to setup the USB-to-Serial adapter found here:
http://serialio.com/products/adaptors/usb_serial.php
with a Windows XP running under the Parallels virtual machine on Apple Mac hardware.

This can be used to connect barcode and RFID scanners to work with Windows XP when running Parallels virtual machine on Apple Mac hardware.

The first step is to configure the USB device settings in Parallels. (tested on Parallels build 1970)

Click on USB Controller under Resources and the following screen should appear:

Select both checkboxes under USB Options:
            -Device Status: Enabled
            -Connection Options: Autoconnect USB devices

Next, launch the Windows Virtual Machine.

Install the drivers for the USB-to-Serial adapter. The Windows drivers can be found here:
http://serialio.com/products/adaptors/usb_serial_WinDesk.php

Plug in the USB-to-Serial adapter.  Your Virtual Machine should recognize the hardware.  You can verify that the adapter has been properly installed by checking
Control Panel > System > Hardware > Device Manager > Ports

Now you can begin using the USB to RS-232 serial adapter on the Windows Virtual Machine on the Mac.

 

If, when you plug in the USB-to-serial adapter, you encounter an error such as this:

Please see this link for a known workaround: USB device issue with Parallels