Preface xxxiii of the chapters on specific entertainment disciplines (lighting, sound, video, etc.) and into their own sections. As a result, the chapters describing the entertainment disciplines are now much smaller and contain lots of references to the more technical sections. Moving the protocol information from individual discipline chapters also makes sense for another reason: Modern protocols increasingly use a layered, transport-independent design. This means they are shifting away from simple protocols that have direct association with hardware interfaces and toward sophisticated command languages that can be communicated using a common network (Ethernet). DMX, for example, was designed as a hardware standard and a command set. The 1986 standard defined everything from the 5-pin XLR connector, to the timing, format, and meaning of the bits travelling over the cable. MIDI, SMPTE Time Code, P-Com, Sony 9-Pin, and similar standards from that era all have close hardware ties. Today, however, why would anyone develop a hardware-intensive standard when they could simply write their own command set and use Ethernet (and associated protocols) as a hardware and data transport standard? Other "legacy" standards like DMX are being moved onto the network as well. ACN, a modern, layered standard, can transmit the dimmer level data cur- rently carried by DMX, and various approaches are now available to transport the MIDI com- mand set over any network (see "Real Time Protocol (RTP) MIDI Payload," on page 315). O BSOLETE S TUFF While there is a lot of new information in this edition, little of what was covered in the second