Below are some photos of an original Cage communicator prop from the collection of celebrated TOS expert and model maker Greg Jein. After it was used in the 1st pilot for Star Trek, filmed during the months of November and December in 1964, this prop was redressed to serve as the Spock controller unit in the early 3rd Season TOS episode "Spock's Brain".
Special thanks to TOS expert Darrell Hyde for his kindness in providing these rare photos for display on this site.
Some screenshots of a communicator prop as used in "The Cage" ...
The redressed communicator as seen in "Spock's Brain" ...