duplexer

1. (electronics) A device that enables communication in two directions over a single path.Examples: "At first, making a duplexer seemed impossible, of all the filters in the cell phone, the specifications for the duplexer were by far the most stringent."; "The HE11 mode emits a Gaussian beam into free space as is required for input to the quasi-optical duplexer attached to the antenna."; "A drawback in the dual duplexer design is that six channels are lost because three band gaps are required."

2. (electronics) A accessory of some printers that automatically flips pages to print on both sides.