May seem like a no-brainer to you but I didn't call myself uninitiated without a reason. I just want to confirm how does the transmitter in a wireless headphone set (eg in the case of Sennheiser RS 120) connect with the original source (TV/HiFi /Computer)? Is it through a cable which plugs into the headphone jack socket in the original source? I understand how the signal gets to the headphones. I have tried to look around the internet but I could not find a direct explanation for how the transmitter receives its signal. I did find this forum and hence the question. Also, is the transmitter unit powered through the main? If so why does the transmitter use 9volt batteries. Thanks for taking the time to look at this.