ABSTRACT
In most professional facilities, high-resolution audio exists primarily as highspeed data. Dialog that was recorded to hard disk or DVD on the set is opened as files in the editor, with no transfer time; audio and video workstations pass content back and forth via Ethernet; and client copies are sent to servers over the Internet. When the phone company made up the rules for audio wiring, most devices' inputs were powered by the audio signal itself. Audio levels were measured in terms of their power, as decibels related to a standard wattage. In 1940, the phone company and radio networks agreed on a standard level for long distance broadcast and telephone lines: 1/1000 watt. Since decibels are ratios, any audio power from the tiniest microphone signal to the biggest amplifier output could be specified in decibels referred to that milliwatt. High-quality Cat-5 cable is built to very rigorous balancing standards, usually much higher than ordinary audio cable.
