Composite video
A single video signal which combines the luminance, chominance and synchronization information using the PAL, NTSC or SECAM standadrs.
EIA-644
An electrical specification for the transmission of digital data. EIA-644 and RS422 are "balanced" data transmission standards that
require two wires per signal. The state of the signal at the receiver is determined by the potential difference between the two wires and not by the difference between the signal on a single wire and ground. Since each wire in the pair is subjected to roughly the same transmission environment, electrical noise adds equally to bouth wires. This "common mode" noise is subtracted at the receiver. This makes both of these standards particularly useful in noisy environments. EIA-644 operates at lower voltage differences
than RS422, providing higher transmission bandwidths. EIA-644 transmitters and receivers also introduce less line-to-line skew, meaning that signal integrity is better preserved even when the transmitter is RS422 and the receiver is EIA-644. EIA-644 is also
commonly known as LVDS (Low Voltage Differential Signaling), sometimes as RS644.
IEEE 1394 (Firewire)
A 1995 Macintosh/IBM PC serial bus interface standard offering high-speed communications and isochronous real-time data services. 1394 can transfer data between a computer and its peripherals at 100, 200, or 400 Mbps, with a planed increase to 2
Gbps. Cable length is limited to 4.5 m but up to 16 cables can be daisy-chained yielding a total length of 72 m. It can daisy-chain
together up to 63 peripherals in a tree-like structure (as opposed to SCSI's linear structure). It allows peer-to-peer device communication, such as communication between a scanner and a printer, to take place without using system memory or the CPU. It is designed to support plug-and-play and hot swapping. Its 6-wire cable is not only more convenient than the SCSI cables but can
supply up to 60 watts of power, allowing low-consumption devices to operate without a separate power cord.
NTSC
National Television Standards Committee: the industry group that formulated the standards for American television. An NTSC signal
is a composite video signal used by televisions and VCRs in North America and some other parts of the world. The NTSC system uses 525 lines per frame, a field frequency of 60 Hz, a 30-frame per second update rate.
PAL
Phase Alternating Line: video format - used in most of Western Europe, Australia and China as well as in various African, South
American and Middle Eastern countries - with a 4:3 image format, 625 lines per frame, a field frequency of 50Hz and 4 MHz video
bandwidth with a total 8 MHz of video channel width. PAL has a 25-frame per second update rate.
RS-170
The encoding standard for 60-Hz black-and-white television signals; it is used as the standard for most monochrome and color
video equipment. See also NTSC, PAL, SECAM. This standard was developed for braodcast television to provide a smoother picture at relatively low (30/25 Hz) frame rate. Beginning at the top of the frame, the camnera reads all the odd-numbered lines (1,3,5 ... )
during the first half-frame time. It then starts at the top again and reads all the even-numbered lines (0,2,4...) during the second half-
frame time. By changing only half the picture lines at a time, the picture has less flicker.
RS422
An electrical standard for the transmission of digital data. See definition for EIA-644.
RGB (Red, Green, Blue)
The abbreviation for the red, green and blue signals, the primary colors of light (and television). Each color signal is transmitted in a
cable of it's own.
SVHS, S-VHS
S-VHS. The Super-VHS high-band video recording format is a consumer, desktop video and industrial production format which
utilizes a component Y/C signal format. It offers better picture resolution, better signal-to-noise performance and elimination of
cross-color and dot crawl interference.
SECAM
Sequentiel Coleur A Memoire: European video standard, used in France and Eastern Europe, with image format 4:3, 819 lines per
frame, 50 Hz and 6 MHz video bandwidth with a total 8 MHz of video channel width. Like the similar PAL standard, it has a 25-frame per second update rate.
USB
(Universal Serial Bus) Serial 4 wire bus architecture for peripheral I/O developed by Compaq, Intel, and Microsoft. It autosenses
(theretically) up to 128 peripherals in a daysy-chain and supports a maximum distance of 5m (16.4') and a maximum data rate of 12
Mbps. USB devices can be unplugged/plugged in without having to reboot your computer. Popular on modern PCs and associayted
computer peripherals (printers, scanners, cameras etc) but also adopted by Apple on their iMac and blue G3 machines onwards.