You can use Virtual PC 3.0 and the serial port. You can use a db9 -> din8 adapter to attach it to your mac's printer or modem port (if you have a Yosemite G3, you have to have the stealth port. If you need to use your modem, you're out of luck). In the VPC preferences map COM1 or COM2 to the Modem or Printer port, and be sure to check the 'non-modem device' preference. Yup, it is slow, but I'd rather have to chew off my fingers than use a Windows box ever again.