IC (integrated circuit) Many A/V products use ICs for processing and amplifying audio signals; higher-quality units use discrete transistors instead.

IEEE1394 See “FireWire.”

i.LINK Sony’s name for their implementation of IEEE1394 (FireWire).

impedance Resistance to the flow of an alternating electrical current.

infrared (IR) The wavelength of light used by remote controls to send commands to components.

interconnect A cable that carries line-level audio signals.

interlaced scanning The technique used in NTSC video in which the odd-numbered scanning lines of the video picture are displayed in one pass from the top of the screen to the bottom, and the even-numbered scanning lines are displayed on the second pass, to form a complete image. Contrast with “progressive scanning.”

interpolation Filling in missing information with a “best-guess” estimate.

in-wall speaker A speaker mounted inside a wall.

inverse telecine See “3:2 pull-down.”

IRE (Institute of Radio Engineers) The measure of brightness in video images. Black is usually defined as 7.5 IRE; white as 100 IRE, with all other brightness levels falling between these two values.

IR repeater A pair of devices,called an “IR sensor” and “IR flasher,” that together relay IR commands from a remote control to components hidden from the remote control’s direct line of sight.