Agree with opjose - you can save a few bucks by using your own transmitter, or get the TTX600 in the deal, but in addition to controlling eight "model" channels, the Interlink was set up as a controller for the RF software, and includes handy control buttons that you can use to manage most of the simulation from the Interlink controller.

Recall that Murphy's Law still applies to RC flying... With the Interlink, you'll never make an early morning trip to the flying field and discover that you left your transmitter sitting on the desk, connected to your PC after a late night practice session ...

If you hook up RF with a transmitter, in addition to using Tx batteries*, in order to change airplanes, airfields or display features you must use either a keyboard or mouse. With the Interlink, you can kick back in your chair and fly, crash, rewind/reset, change airplanes and control many RF features from the Interlink control panel...

* requiring either frequent replacement, or buying and managing separate sets for flying and RF.