Term	Definition	Demo
Audio Interconnect Cable	A shielded wire used to link the audio signal output of one device to the input of another audio device.
Balanced Connection	A method of interconnecting audio components using a three-wire cable in which there are two signal wires and one ground wire, all of which may be inside a cylindrical shield that is also grounded. The two signal conductors both have the identical impedances to the common ground terminal, hence the name Balanced. Because of this such interconnections are highly immune to ground-originated noises and hum. It is widely used in professional audio systems which routinely have very long cable runs and very complex interconnections of signal and power grounds. The XLR plug is commonly used. See: Unbalanced Connection.
Banana Plug and Jack	A largish, pin-type, connector commonly used to connect loudspeakers to power amplifiers.
Bus	A signal distribution system, normally employing wire, optical fiber, which enables many components to be operated from a single control unit without each being individually linked to it. Some bus systems have two-way communication.
Coaxial Cable	A transmission line in which a central conductor is located within a cylindrical outer conductor, separated by insulation. Can be designed to have specific characteristic impedances at radio and TV frequencies to minimize losses. Sometimes used in the much less demanding role of interconnect cables at audio frequencies, where they function as simple shielded wires.
Component Video	A video signal consisting of three components: red/green/blue (RGB) or a Color Difference method going by one of several names: Y,U,V or Y, Pb, Pr or Y, B-Y, R-Y. The latter is the method of video storage on DVD's and the component connection is the preferred way to communicate video infomation to displays. The green, blue and red cables may be terminated in either RCA or BNC plugs. See: Chrominance, Luminance, RCA, S-Video, BNC.
Composite Video	A video signal in which the chrominance and luminance signals are combined, along with synchronizing signals. These tend to use cables, looking like yellow audio cables, with RCA connectors. This is the most basic form of video found on virtually all TV's, VCR's, etc. See: Chrominance, Luminance, RCA, S-Video, Component Video.
Digital Satellite System	A broadcast system in which digital video and audio signals are delivered to customers' homes by means of signals radiated from a satellite in stationary orbit and received by a small dish antenna.
Digital Television	A generic term that describes any of several systems capable of delivering digital video signals. High Definition (HDTV), Intermediate Definition (IDTV), Enhanced-Definition (EDTV) and standard definition (SDTV) are some of the systems. See: HDTV, IDTV, EDTV, SDTV.
Direct Subwoofer Input	A connection bypassing the internal crossover of a subwoofer, to allow the connection of A/V receivers and surround processors that already contain their own subwoofer crossovers and adjustments. See: Crossover
Multiroom	A feature of custom whole-house systems, and of some AV Receivers, allowing sound to be delivered to loudspeakers in other rooms, without interfering with what is happening in the main entertainment room.
Parallel Connection	Connecting two or more devices across the same terminals so that each device carries the full applied voltage. In loudspeakers, parallel connection of two identical units halves the impedance seen by the power amplifier, which can create problems with amplifiers not able to drive low impedances. For example, two 6-ohm loudspeakers operating together will present a 3-ohm load, which is below the safe operating load range for many power amplifiers. This is a consideration in the A, B, A+B loudspeaker switching feature of A/V receivers. See Series Connection.
RCA Plug/Socket	Radio Corporation of America, which gave its name to the very common plug and socket used for line level audio and many video interconnections.
Series Connection	A circuit where components are wired sequentially, in head-to-tail fashion, across a pair of terminals. The terminal voltage is then divided between them in proportion to their impedance characteristics. Each of two identical loudspeakers would receive half of the voltage, and half of the power, delivered to the series combination. This connection is often used in A/V receivers in A, B, A+B loudspeaker switching, to prevent confronting the power amplifiers with loads they cannot drive. The tradeoff is reduced maximum power to each loudspeaker. See Parallel Connection.
Series-Parallel Connection	A circuit where there are components wired in series and also in parallel to get the desired result out of the combination. This is often used in multi-loudspeaker systems to optimize the impedance seen by an amplifier.
Unbalanced Connection	An interconnection between audio components in which there are two conductors, signal and ground. The 'unbalanced' aspect of this connection is that, since ground is the reference, each of the two signal leads has a very different (unbalanced) impedance relationship to to the reference. This is of no consequence unless there are noises or hum potentials in the grounding of the interconnected components. Commonly employs a coaxial cable, in which the outer cylindrical shield serves as the ground connection. If hum problems are found, it is possible to selectively break the ground connection, and thus break the ground loop. See: Balanced Connection, Coaxial, Ground, Ground Loop.