Breakout box - Definition and Overview

A breakout box is a piece of test equipment used for diagnosing problems in computer communications, typically over a serial port. The breakout box sits between two pieces of equipment and usually has some LED's to display the status of the different signals in the serial cable. It will also often have DIP switches to let the user connect or disconnect different signals in the cable, and it will usually have connector pins that lets the user short pins together using electrical jumpers.

It would be nice to have a photo here.