B&R Automation PC 620, User Manual

Page: 566 / 594

566
Appendix A • Glossary
Automation PC 620 with 945GME N270 CPU board User's Manual V 1.10
UART
An abbreviation for " U niversal A synchronous R eceiver- T ransmitter". A module generally
consisting of a single integrated circuit that combines the circuits required for asynchronous
serial communication for both sending and receiving. UART represents the most common type
of circuit in modems for connecting to a personal computer.
UDMA
An abbreviation for " U ltra D irect M emory A ccess". A special IDE data transfer mode that allows
high data transfer rates for drives. There have been many variations in recent times.
UDMA33 mode transfers 33 megabytes per second.
UDMA66 mode transfers 66 megabytes per second.
UDMA100 mode transfers 100 megabytes per second.
Both the mainboard and the hard drive must support the specification to implement
modifications.
UPS
Abbreviation for " U ninterruptible P ower S upply". See "UPS".
USB
An abbreviation for " U niversal S erial B us" A serial bus with a bandwidth of up to 12 megabits per
second (Mbit/s) for connecting a peripheral device to a microcomputer. Up to 127 devices can
be connected to the system using a single multipurpose connection, the USB bus (e.g. external
CD drives, printers, modems as well as the mouse and keyboard). This is done by connecting
the devices in a row. USB allows devices to be changed when the power supply is switched on
(hot plugging) and multi-layered data flow.
UPS
An abbreviation for " U ninterruptible P ower S upply". The UPS supplies power to systems that
cannot be connected directly to the power mains for safety reasons because a power failure
could lead to loss of data. The UPS allows the PC to be shut down securely without losing data
if a power failure occurs.
UXGA
Abbreviation for " U ltra E xtended G raphics A rray" Generally a screen resolution of 1600 × 1200
pixels (aspect ratio 4:3, 12:9).
VGA
An abbreviation for " V ideo G raphics A dapter". A video adapter which can handle all EGA
(Enhanced Graphics Adapter) video modes and adds several new modes.
U
V