AND I ONCE RAN AN OLD TELEPHONE SWITCHBOARD BACK IN 1955. I WORKED AS A RECEPTIONIST AND A SWITCHBOARD OPERATOR AT THE FRIARS CLUB IN NEW YORK. THE FRIARS CLUB, OF COURSE, IS THE MOST PRESTIGIOUS ...

Typically used in test labs and controlled by software, the physical layer switch resembles the old telephone switchboard, which cross-connected an input telephone line to an output line.