What Is a Breakout Box?

Breakout boxes are devices that can be used to achieve greater access to the individual wires in a harness without damaging them or the plug they connect to. One common use for breakout boxes is to allow for the in-line modification of video and audio signals. They are sometimes used in recording contexts and are also available for some computer sound cards. Breakout boxes are also often used for various types of electrical diagnostic purposes. A breakout box with the correct plug type can be useful in the diagnosis of some computer issues, and similar devices are commonly used by automotive technicians.

The term "breakout box" refers to the fact that these devices are used to break the individual wires out of compound harnesses. To this end, a breakout box must be equipped with the specific type of plug that is compatible with the harness connector being worked with. The internal wiring of the box then bridges each individual wire in the harness with larger jacks, connectors or testing points that are easier to work with. In some cases, a box can plug directly into a harness in place of another component, though other breakout boxes are designed to be connected in-line.

There are many kinds of breakout boxes, though they can all be categorized into two basic groups. The first type of breakout boxes are used to enhance or otherwise alter video and audio signals. These boxes are typically used by recording artists, sound engineers and other similar professionals. The compound wires typically used to transmit a number of different video and audio signals through a single cable can be plugged into a breakout box, providing easy access to each.

The other main use for breakout boxes is in electrical diagnostics. Many wiring harnesses in a variety of different applications are very tightly packed and connect to similarly dense plugs. These types of wires and plugs can sometimes be severely damaged by electrical probes, making it difficult to perform diagnostic work. One example is breakout boxes designed for use with the serial or parallel ports of computers. These devices are capable of providing technicians with greatly improved access to these ports for diagnostic work.

Breakout boxes are also common in automotive diagnostics, particularly concerning electronic control modules (ECMs). These components often control everything from ignition timing to fuel mixture and can have dozens or even hundreds of wires connected to them. The connectors that these modules use are proprietary, and even different vehicles from the same manufacturer can use different plugs. A breakout box with the correct plug can typically be installed in-line, allowing access to the necessary wires even when a vehicle is running.