| Term |
Definition |
| I/O |
A commonly used abbreviation for Input/Output. |
| I2C |
Integrated Interconnect. |
| IA |
Instrumentation Amplifier. |
| IC |
Integrated Circuit. A tiny complex of electronic components and their connections that is produced in or on a small slice of material (as silicon). |
| IDCT |
Inverse Discrete Cosine Transform. |
| Idle Channel Noise |
The total signal energy measured at the output of the device when the input of the device is grounded. Unless otherwise specified, this is a wide-band noise measurement. |
| IDVC |
Integrated Data/Voice Channel. |
| IEE |
Institute of Electrical Engineers. |
| IEEIE |
Institute of Electronics and Electrical Incorporated Engineers. |
| IF |
Intermediate Frequency. |
| IGRP |
Internal Gateway Routing Protocol - A protocol developed by Cisco Systems to address the problem of routing within a large network of general topology comprised of segments having different bandwidth and delay characteristics. |
| ILD |
Injection Laser Diode. |
| Illegal Video |
Some colors that exist in the RGB color space can't be represented in the NTSC and PAL video domain. For example, 100% saturated red in the RGB space (which is the red color on full strength and the blue and green colors turned off) can't exist in the NTSC video signal, due to color bandwidth limitations. The NTSC encoder must be able to determine that an illegal color is being generated and stop that from occurring, since it may cause over-saturation and blooming. |
| IMA |
Inverse Multiplexing for ATM; The inverse multiplexing of an ATM cell stream cell stream over multiple physical links (DS1/E1, DS3/E3). |
| Image Buffer |
For all practical purposes, an image buffer is the same as a frame buffer. An image is acquired and stored in the image buffer. Once it is in the image buffer, it can typically be annotated with text or graphics or manipulated in some way, just like anything else in a frame buffer. |
| Image Compression |
Image compression is used to reduce the amount of memory required to store an image. |
| Impedance |
The combined effect of the electrical resistance, capacitance and inductance of a transmission medium. |
| Impedance discontinuity |
A point at which the electrical properties of a transmission medium change. Important because at high frequencies this may result in reflections and possible malfunction. |
| Inband Signaling |
Signaling that uses the same path as a message and in which the signaling fre-quencies are in the same band used for the message. |
| Incident Angle |
The angle between the subject light wave and a plane perpendicular to the subject optical surface. |
| INFONET |
A packet switched network implemented in the U.S.A. |
| InGaAs |
Indium Gallium Arsinide. |
| InGaAsP |
Indium Gallium Arsinide Phosphide. |
| InP |
Indium Phosphide. |
| INTELPAK |
A packet switched network implemented in Hong Kong. |
| Inter Office Trunk |
A direct connection between telephone company central offices. |
| Interference |
Noise or other distortion during the transmission of data which may cause errors. |
| Interlaced |
An interlaced video system is one where two interleaved fields are used to generate one video frame. Therefore, the number of lines in a field is one-half of the number of lines in a frame. In NTSC, there are 262.5 lines per field (525 lines per frame), while there are 312.5 lines per field (625 lines per frame) in PAL. Each field is drawn on the screen consecutively -- first one field, then the other. |
| Interlaced Scanning |
In a television display, interlaced scanning refers to the process of re-assembling a picture from a series of electrical (video) signals. The "standard" NTSC system uses 525 scanning lines to create a picture (frame). The frame/picture is made up of two fields: The first field has 262.5 odd lines (1,3,5...) and the second field has 262.5 even lines (2,4,6...). The odd lines are scanned (or painted on the screen) in 1/60th of a second and the even lines follow in the next 1/60th of a second. This presents an entire frame/picture of 525 lines in 1/30th of a second. |
| Intermodulation Distortion |
A transmission effect which causes a signal to appear at the extremes of its voltage swing. (Also at the zero level). |
| Internet address |
A 32-bit address assigned to hosts using TCP/IP. The address is written as four octets separated with periods (dotted decimal format) that are made up of a network portion and a host portion to make routing of information using the address easier. |
| Internet Protocol |
A network layer protocol developed in conjunction with Transport Control Protocol (transport layer), originally in the Arpanet network which is now supported by many versions of Unix and used by a wide range of network operating systems. |
| Interrupt |
A signal which is used to interrupt an on going process so that another process (defined in some way by the interrupt can be executed. After the second process is complete the interrupted device will return to the original process. |
| Intersymbol Interference |
Interference in a digital (or any Time Division) transmission system caused by a symbol in one signaling interval being spread out and overlapping the sample time of a symbol in another signal interval. |
| Intrinsic Jitter |
The jitter introduced by the PLL. Measured by applying a reference signal without jitter to the input, and measuring the jitter at the output. |
| IP |
Internet Protocol - Designed for use in interconnected systems of packet-switched computer communication networks, IP is the ubiquitous protocol on which the Internet runs. Logically, two machines communicate through IP datagrams, which are then sent over the link layer as packets. Runs on top of link layers like Ethernet, Packet over SONET or ATM. Defined in IETF RFC791 & STD5. |
| IRD |
Integrated Receiver/Decoder. |
| ISA |
Instrument Society of America. |
| ISDN digital subscriber line (IDSL) |
A type of DSL that uses ISDN transmission technology to deliver data at 128kbps into an IDSL "modem bank" connected to a router. |
| Isochronous |
The time characteristics of an event or signal recurring at known periodic time intervals. |
| Isochronous Ethernet, Isoethernet |
A LAN technology that adds 6 Mb/s of isochronous services to a cable that also carries normal 10 Mb/s Ethernet traffic. Allows voice and/or video to be carried on the same cable as data traffic. |
| Isochronous Transmission |
Any transmission method where there is a fixed and constant time interval between any two significant events. |
| ISPBX |
Integrated Systems PBX. |
| IVD |
Integrated Voice Data. |
