SimpleUSB supports using a parallel port to interface with a radio for PTT, COR, CTCSS and static output. The documentation on the Drupal site has been updated to reflect this feature. http://ohnosec.org/drupal/node/193 This has been in simpleUSB for a long while but Drupal documentation was way behind. I’ve not tested CTCSS decoding myself but I know PTT and COR work.