In theatrical productions, the channel hookup is a printout of a lighting database such as Lightwright

Lightwright

Lightwright is a spreadsheet/database program created specifically for theatrical lighting applications. The program is used to sort and manage data related to lighting designs and to generate design paperwork...

 that organizes all the lighting information for a stage show by the channel number associated with the lighting equipment and limits the information associated with a particular lighting instrument such that a designer or electrician can access needed information rapidly and efficiently.

Lighting equipment is often organized by lighting system thereby granting coherence to consecutive channel numbers. Channels 1 through 10 might be Frontlight

Frontlight

A frontlight is a means of illuminating a display device, usually a liquid crystal display , which would otherwise be viewed in ambient light. This improves its performance in poor lighting conditions. Frontlights are inferior to backlights and are usually found as an auxiliary feature.An LCD...

 while 21 through 30 could be Sidelight

Sidelight

A sidelight is a window, usually with a vertical emphasis, that flanks a door. Sidelights are narrow, usually stationary and found immediately adjacent doorways...

 from left. In Repertory Opera

Opera

Opera is an art form in which singers and musicians perform a dramatic work combining text and musical score, usually in a theatrical setting. Opera incorporates many of the elements of spoken theatre, such as acting, scenery, and costumes and sometimes includes dance...

and other large venues channel numbers are often granted to lighting equipment by position as the purpose of the light will change from show to show.

A Channel Hookup will commonly include Channel, Dimmer, Color, Template and Purpose information