220 Part 4 · Standards and Protocols Used in Entertainment Single-channel color scrollers and moving lights are addressed in a similar manner (see fig- ure). The address is set in the target devices using a scheme determined by the manufacturer. Some have the user set the actual starting DMX slot number as the fixture address, as described above; other manufacturers think it's easier to have the user set a "rack," "device," or "unit" number. With this "rack number" approach, the dimmer packs above would be set so that the first is rack 1, the second, rack 2, and the third, rack 3. This approach makes things easier in small systems, but can get confusing for larger systems. Each manufacturer decides how the DMX address will be configured in their products. Some use buttons and an electronic display; others use "thumbwheel" switches, which mechanically display the setting. Some manufacturers still opt for the cheapest and most confusing way: "DIP" 4 switches. This small bank of switches enables the user to set a number in binary. Con- fusion arises because some manufacturers specify that the number be in the range starting at 0, while others start at 1. In addition, an 8-position DIP switch can represent only 256 possible combinations (11111111 2 ), so, to be able to listen to any of the 512 possible control slots, an additional switch must be used. U NIVERSES Installations needing more than 512 slots simply use multiple DMX "universes," 5 with sec-