Both MediaLab and DirectRT can communicate with the outside world. Many of our users have successfully interfaced with external systems (biological monitoring, eye positition tracking, etc).
Here are some past discussions regarding...
...an eye tracking setup:
http://empirisoft.com/support/showthread.php?t=152
http://www.empirisoft.com/support/showthread.php?t=131
...a BioPac System:
http://empirisoft.com/support/showthread.php?t=573
...third party I/O interface cards:
http://empirisoft.com/support/showthread.php?t=584
...synchronizing 2 machines:
http://empirisoft.com/support/showthread.php?t=762
If you could describe in a bit more detail what you'd like to accomplish, we can certainly offer more suggestions.
John