Review on Manhattan 172851: Audio Speaker and Headset Switching Hub by Tony Fuchs

Mine came with detailed instructions - in Chinese (or other figurative language). So I had to experiment. There are two connectors - one for your computer's speaker/headphone output and the other for your computer's microphone input. There are four connectors.1. Insert the headphone plug into the headphone jack on the computer2. Plug your headphones into the headphone jack on your device3. Connect an external speaker to the speaker port on the device4. Turn the volume control all the way up (meaning no attenuation of the signal. There is no actual amplification as such).5. Now the left button toggles the output signal between speakers and headphones.6. Insert the microphone plug into your computer's microphone jack. This will disable your computer's internal microphone7. Connect an external microphone to the microphone jack on your device. Now the external microphone provides input for your computer, and the right button mutes/unmutes the sound. This leaves a 2.5mm speakerphone jack on the device. I have no way of testing this. Bottom line, this is a pretty comprehensive distribution block. I haven't experienced the buzzing or scratching that some others have reported.