Chapter 22 · DMX512-A 227 (also known as repeaters or distribution amplifiers) should be used (because they provide redundancy), so that if the connection between the splitter and a device is damaged, the other connections will still continue to function. DMX connects very high-power devices (such as dimmer racks) to delicate, low-power, electronic devices (such as consoles). If a high-voltage failure occurs in a dimmer rack, it is quite possible for the voltage to travel back up the DMX data link and blow up the console; it is also possible for a failure in one dimmer rack to damage the control electronics of another. For this reason, DMX links should, if at all possible, be electrically isolated (see "Iso- lation," on page 39), either optically (most common) or galvanically (i.e., with Ethernet). With an isolated system, there is no electrical connection between the DMX input and the output, and high-voltage or other electrical failures are isolated from delicate control electronics. Opti- cal isolation is often combined with splitter functionality into units called "opto splitters." EIA-485 was not originally designed for long-haul data transmission, and did not address a signal grounding scheme. This caused some problems in DMX installations where manufac- turers used different grounding schemes, so DMX512-A specifies a preferred grounding TL