Often a device (like a Sony TV) has the ability to understand commands not included on it's original remote. For example, most remote controls have a simple "POWER" toggle button which turns the device both on and off. Sony TV's have the ability to respond to an ON only or an OFF only command. These commands are very useful when creating macros to control your home theater system. A discrete ON command will not turn you system OFF it is already ON. Likewise a disctrete OFF command will not turn your system ON if it is already OFF. Your macros can be "State (on or off?)" independant. There are often several other features you can find discrete codes for that allow you control over your devices you never had, or that took several button presses on the original remote. Direct access to specific input. Switching of S-video or composite video input, etc..

Dave