I

[This is preliminary documentation and subject to change.]

ICP

Independent content provider. See content provider.

IHV

See independent hardware vendor.

independent hardware vendor

(IHV) A person or company that develops and sells hardware, in this case for Broadcast Architecture.

independent software vendor

(ISV) A person or company that develops and sells software, in this case for Broadcast Architecture.

infrared

(IR) Defines a spectrum of electromagnetic radiation with frequencies in the spectrum less than those of visible light. Remote control units usually communicate with home televisions and VCRs by using infrared signals.

integrated receiver/decoder

(IRD) A subscriber terminal, such as the set-top box used for satellite television systems. In the case of Broadcast Architecture, the IRD is the broadcast receiver card.

Integrated Services Digital Network

(ISDN) A type of phone line used to enhance data transmission speed. Data can be transmitted over ISDN lines at speeds of 64 or 128 kilobits per second, whereas standard phone lines generally limit modems to top speeds of 20 to 30 kilobits per second. An ISDN line must be installed by the phone company.

interactive television

The combination of a video program and multimedia enhancement elements such as hypertext links, graphics, text frames, sounds, and animations.

interface

In computing in general, the point where two elements connect so that they can work with one another, for example the connection between an application and an operating system or between an application and a user (the user interface).

In C++ programming, a collection of related methods exposed by a given class of objects. The methods in an interface are procedures that can be performed on or by those objects.

The Component Object Model (COM) architecture has become the foundation for interfaces that work with the Microsoft® Windows® 98 and Microsoft® Windows NT® operating systems. In earlier programming for Windows, an application programming interface (API) consisted of functions that one piece of software could call to gain access to services provided by another piece of software.

interlacing

A video display technique, used in current analog televisions, in which the electron beam refreshes (updates) all odd-numbered scan lines in one field and all even-numbered scan lines in the next. Interlacing takes advantage of both the screen phosphor's ability to maintain an image for a short time before fading and the human eye's tendency to average subtle differences in light intensity. By refreshing alternate lines, interlacing halves the number of lines to update in one screen sweep. An alternative video display technique, used in computer monitors, is progressive scanning. In progressive scanning, the image is refreshed one line at a time.

Internet

Generically, a collection of networks interconnected with routers. "The Internet" is the largest such collection in the world. The Internet has a three-level hierarchy composed of backbone networks, midlevel networks, and stub networks.

Internet channel broadcasting

A technology to gather and redistribute World Wide Web content. Applications that use Internet channel broadcasting package a series of Web pages or sites and deliver them to broadcast clients at regular intervals. They can provide this content to a broadcast server for retail delivery to subscribing clients, or they can provide the content on a local area network (LAN).

Internet Protocol

(IP) The primary network layer of Internet communication, responsible for addressing and routing packets over the network. IP provides a best-effort, connectionless delivery system that does not guarantee that packets arrive at their destination or that they are received in the sequence in which they were sent. See also Transmission Control Protocol/Internet Protocol and User Datagram Protocol/Internet Protocol.

IP

See Internet Protocol.

IP multicast address assignment

The process by which transient Class D Internet Protocol (IP) multicast addresses are allocated. Each address must be assigned uniquely across the system for a specific time period. Once that time period elapses, the address returns to the available pool. In Broadcast Architecture, these addresses are used to identify data streams being broadcast, both at the head end and in broadcast client systems in the home.

IR

See infrared.

IR/D

See integrated receiver/decoder.

ISDN

See Integrated Services Digital Network.

ISV

See independent software vendor.