B&R Industries Automation PC 620, Руководство пользователя

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Appendix A • Glossary
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485 Automation PC 620 User's Manual V 1.90
TXD
An abbreviation for »Transmit (TX) Data« A line for the transfer of serial data sent from one
device to another - e.g. from a computer to a modem. For connections complying with the RS-
232-C standard, the TXD is connected to pin 2 of the plug.
UART
An abbreviation for »Universal Asynchronous Receiver-Transmitter« Generally, a module
consisting of a single integrated circuit, which combines the circuits required for asynchronous
serial communication for both sending and receiving. UART represents the most common type
of circuit in modems for connection to a personal computer.
UDMA
An abbreviation for »Ultra Direct Memory Access« A special IDE data transfer mode that allows
high data transfer rates for drives. There have been many variations in the recent times.
The UDMA33 mode transfers 33 megabytes per second.
The UDMA66 mode transfers 66 megabytes per second.
The UDMA100 mode transfers 100 megabytes per second.
A condition for modifications is that both the mainboard and the hard drive support the
specification.
UPS
An abbreviation for »Uninterruptible Power Supply« UPS supplies power to systems which
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.
USB
An abbreviation for "Universal Serial Bus". 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, printer, 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.
UXGA
Abbreviation for »Ultra Extended Graphics Array« Generally a screen resolution of 1600 × 1200
pixels (aspect ratio 4:3, 12:9).
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