ging can be used to move and store medical X-rays, for engineering and design applications that allow engineers to develop 3-D images of a products or components for the purpose of design-refinement, and to store large quantities of documents. impedance The ratio of voltage to current as it is measured along a transmission circuit. in-band signaling Networks exchange information between nodes through the use of signaling. In-band signaling uses the communications path to exchange such information as request for service, addressing, disconnect, busy, etc. In-band signaling has been largely replaced by out-of-band signaling, an example of which is the ITU-T's Signaling System Number 7 or SS7. input The data or signals entering a computer or, more generally, the signal applied to any electronic device or system. input selector A switch or routing device that is used to select video inputs in a digital picture manipulator or keying device. Glossary of Terms integrated circuit An electronic device IC's are made by layering semiconductive materials and packaging both active and passive circuits into a single multi-pin chip. intelligent peripheral In the AIN, the intelligent peripheral or IP collects information from designated "triggers" and issues SS7 requests based on that information. inter-LATA Communications that cross a LATA boundary and, therefore, must be carried by an IXC in accordance with the MFJ. interactive Action in more than one direction, either simultaneously or sequentially. In interactive video there is a bi-directional interplay between two or multiple parties, this is different from television, which is a send-only system that does not allow the receiver to respond to the signal. interactivity The ability of a video system user to control or define the flow of information, including the capability of communicating in return on a peer-to-peer basis. interexchange carrier IXC or IEC. The long distance companies in the US that provide inter-LATA telephony and communications services. This concept is g