A:Answer Hi, Fred! Those are great questions, and I hope this helps.
For your first question: yes, you can use the QLink with a mono audio source if you use a 3.5mm mono-to-stereo adapter. You will be plugging the QLink into the adapter and then plugging the adapter into your audio source, so the adapter will need a 'female' stereo connector on one end and a 'male' mono connector on the other end.
For your second question: no, the QLink transmitter does not need to be in view of your headset because the sound is transmitted via Bluetooth instead of infrared. As long as you are within 33 feet of the QLink, all you need in order to receive the transmitted sound is a headset (or earphones, streamer, etc.) that is enabled for A2DP Bluetooth.
If you still have questions about the QLink, please visit www.ClearSounds.com/contact-us or call 800-965-9043 to get in touch with our awesome Customer Solutions Team. Thanks! --JP