code. The information here comes from those libraries. A basic Final Scratch setup consists of five pieces of equipment. A computer running a compatible software, usually Native Instrument's Traktor The ScratchAmp Two turntables or two CD decks made for DJing Two time coded vinyl records or time coded CDs An audio DJ mixer. ScratchAmp The ScratchAmp is a FireWire (FS 2, FS Open) or USB (FS 1) audio device. It has two phono/line stereo level inputs to read the timecode from the record or the CD, and two line level stereo outputs to feed into the audio DJ mixer line channels. It also has two phono stereo outputs for pass-through of the actual phono audio signal. This is useful for DJs who wish to play both digital audio tracks AND traditional vinyl; allowing them to switch between the two sources without disconnecting or re-connecting audio jacks in the middle of a DJ set. The ScratchAmp does not store any audio on its own, it is simply a purpose built external Soundcard. It communicates with a PC—usually a laptop—over the FireWire or USB connection. The laptop uses Final Scratch compatible software (typically Traktor DJ Studio) to interpret the timecode signal from the supplied special vinyl/CD, then play back a digital audio file based on that signal, allowing traditional DJ vinyl control of MP3, WAV and Apple AAC audio files. The Laptop software then sends audio data back, over the same FireWire/USB connection to the scratch amp, which then sends an audio signal out through the line level output, for playing through a DJ Mixer or Amp. Audio/data routing A step by step series of events detailing how Final Scratch operates; Timecoded audio signal pressed onto vinyl/CD picked up by vinyl/CD turntable Signal routed into ScratchAmp via phono connection, then into the PC via USB or FireWire DJ software decodes timecode signal and determines position, speed and direction the Vinyl/CD is being played or manipulated DJ software plays the selected "mapped" digital audio file synchronous to the vinyl/CD playback Digital audio file audio signal is sent to the Scratchamp phono connectors for connection to a DJ mixer or amp Vinyl/CD time code The most complex piece of the Final Scratch setup is the code pressed onto the vinyl. A 1200 hertz amplitude modulated sine wave is pressed into the left and right channels with a phase difference of 90 degrees. Each channel