why the seemingly arbitrary dot was there.
Me too. My own theory was that the backing section was a miniaturization of ST:TMP's black Perscan buckle (which supposedly measured biorhythms and sent vital info back to the sick bay's computer), which similarly had a round button on one side and squares on the other.
Back in the day, I had decided they were the new design (and location) of the perscan devices from TMP.
Ha! Great minds think alike!