I want to know the answer to the following question:
What is an example of a device that uses free space optic communications?
All the background I'm provided with is that "This is especially useful in medical equipment where the signals from a low-voltage sensor circuit (usually battery-powered) in contact with a living organism must be electrically isolated from any possible electrical failure in a recording or monitoring device operating at potentially dangerous voltages.". Is that enough to answer the question?
Answer: no