Appendix B • Reference and Glossary
Extron • User’s Manual • RGB 320 Switching Interface System
RS-232 –
An Electronic Industries Association (EIA) serial digital interface standard
specifying the characteristics of the communication path between two devices
using D-type connectors. This standard is used for relatively short range
communications and does not specify balanced control lines. A serial control
standard with a set the number of conductors, data rate, word length and type of
connector to be used. Also specifies component connection standards with regard
to computer interface. Also called RS-232-C, which is the third version of the
RS-232 standard, which is functionally identical to the CCITT V.24 standard.
SECAM –
Sequential Couleur Avec Memoiré, translated as
Sequential Color with Memory.
A composite color transmission system that potentially eliminates a need for both
a color and hue control on the monitor. One of the color difference signals is
transmitted on one line and the second is transmitted on the second line. Memory
is required to get both color difference signals for color decoding. SECAM is used
in France, Africa, Asia, Russia, Saudi Arabia and many Eastern European
countries. Similar to PAL, but it produces color signals in a different manner. 625
horizontal scan lines, 50 fields per second (625/50).
Serial port –
An input/output connection on the computer that allows it to communicate with
other devices in a serial fashion – data bits flowing on a single pair of wires. The
serial port is used with RS-232 protocol.
SMPTE –
Society of Motion Picture and Television Engineers. A global organization, based
in the United States, that sets standards for baseband visual communications.
This includes film as well as video standards.
SMPTE pattern –
The video test pattern consisting of color, black and white bands used as a
standard for setting up video equipment.
Software –
The programs used to instruct a processor and its peripheral equipment.
Switcher –
Term often used to describe a special effects generator, which allows the
operator to switch between video camera signals. Switchers are often used in
industrial applications to switch between video cameras monitoring certain areas
for display on a monitor or system of display devices.
Sync –
In video, a means of synchronizing signals with timing pulses to insure that each
step in a process occurs at exactly the right time. For example, horizontal sync
determines exactly when to begin each horizontal line (sweep) of the electron
beam. Vertical sync determines when to bring the electron beam to the top-left of
the screen to start a new field. There are many other types of sync in a video
system. (Also called
sync signal or sync pulse.)
S-VHS –
Super-Video Home System. A high band video recording process for VHS that
increases the picture quality and resolution capability. See S-Video.
S-video –
The composite video signal is separated into the Luminance (Y; black and white)
and the Chrominance (C; color).
Terminal –
A device, typically having a keyboard and display, that is capable of sending text
to and receiving text from another device, a network, etc.
Termination –
A load, or impedance, at the end of a cable or signal line used to match the
impedance of the equipment that generated the signal. The impedance absorbs
signal energy to prevent signal reflections from going back toward the source. For
video signals, termination impedance is typically 75 ohms.
Vertical interval –
The synchronizing information that is presented between fields, and then signals
the picture monitor to return to the top of the screen to start another vertical scan.
Z –
A symbol for impedance.
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