The connecting block is the central hub of an infrared extender system.  It takes the inputs from any infrared receivers and distributes them out to the IR emitters that re-broadcast the signals to your AV gear wherever it may be located.

CB-140_1

The Russound CB-140 makes it easy to connect infrared accessories together. The hub of an IR repeater system, it receives signals from remotely located infrared receivers and channels them to your source components and other equipment.