The IR (infrared) blaster (aka IR emitter aka IR controller) is 9 feet long and was developed to enable Control Center to control a TV that is not within line of sight. In other words, if Control Center is hidden in a closed cabinet or far away from your TV, the IR emitter will help get IR signals to your TV for power and volume controls.
You can also use the IR emitter to control an AVR or other device that is not within line of sight (if your TV is already being controlled reliably without IR).
The IR emitter cable plugs into the 3.5mm port on the back of Control Center. The other end of the emitter needs to be positioned in front of (and pointed toward) the device's IR window in order to work effectively. IR signals needs direct line-of-site (between the emitter and IR window on the target device) in order to function, so positioning it properly is very important.
Note: The control center unit itself also emits IR from within. You may be able to communicate directly with your devices with IR by placing control center strategically within your entertainment system setup. IR needs line-of-sight so keep that in mind when placing control center and any IR blasters.