[Terms and Abbreviations] Universal Serial Bus Specification(1)

ACK                             Handshake packet indicating a positive acknowledgment.

Active Device                     A device that is powered and is not in the Suspend state.

Asynchronous Data         Data transferred at irregular intervals with relaxed latency requirements.

Asynchronous RA         The incoming data rate, Fsi, and the outgoing data rate, Fso, of the RA process

are independent (i.e., there is no shared master clock). See also Rate

Adaptation.

Asynchronous SRC         The incoming sample rate, Fsi, and outgoing sample rate, Fso, of the SRC

process are independent (i.e., there is no shared master clock). See also

Sample Rate Conversion.

Audio Device                 A device that sources or sinks sampled analog data.

AWG#                     The measurement of a wire’s cross section, as defined by the American Wire

Gauge standard.

Babble                     Unexpected bus activity that persists beyond a specified point in a frame.

Bandwidth                 The amount of data transmitted per unit of time, typically bits per second (b/s)

or bytes per second (B/s).

Big Endian         A method of storing data that places the most significant byte of multiple-byte

values at a lower storage addresses. For example, a 16-bit integer stored in big

endian format places the least significant byte at the higher address and the

most significant byte at the lower address. See also Little Endian.

Bit             A unit of information used by digital computers. Represents the smallest

piece of addressable memory within a computer. A bit expresses the choice

between two possibilities and is typically represented by a logical one (1) or

zero (0).

Bit Stuffing             Insertion of a “0” bit into a data stream to cause an electrical transition on the

data wires, allowing a PLL to remain locked.

b/s             Transmission rate expressed in bits per second.

B/s             Transmission rate expressed in bytes per second.

Buffer                 Storage used to compensate for a difference in data rates or time of occurrence

of events, when transmitting data from one device to another.

Bulk Transfer         One of the four USB transfer types. Bulk transfers are non-periodic, large

bursty communication typically used for a transfer that can use any available

bandwidth and can also be delayed until bandwidth is available. See also

Transfer Type.

Bus Enumeration             Detecting and identifying USB devices.

Byte                 A data element that is eight bits in size.

Capabilities             Those attributes of a USB device that are administrated by the host.

Characteristics             Those qualities of a USB device that are unchangeable; for example, the

device class is a device characteristic.

Client                 Software resident on the host that interacts with the USB System Software to

arrange data transfer between a function and the host. The client is often the

data provider and consumer for transferred data.

Configuring Software

Software resident on the host software that is responsible for configuring a

USB device. This may be a system configurator or software specific to the

device.

Control Endpoint                 A pair of device endpoints with the same endpoint number that are used by a

control pipe. Control endpoints transfer data in both directions and therefore

use both endpoint directions of a device address and endpoint number

combination. Thus, each control endpoint consumes two endpoint addresses.

Control Pipe             Same as a message pipe.

Control Transfer             One of the four USB transfer types. Control transfers support

configuration/command/status type communications between client and

function. See also Transfer Type.

CRC                 See Cyclic Redundancy Check.

CTI                 Computer Telephony Integration.

Cyclic Redundancy Check (CRC)

A check performed on data to see if an error has occurred in transmitting,

reading, or writing the data. The result of a CRC is typically stored or

transmitted with the checked data. The stored or transmitted result is

compared to a CRC calculated for the data to determine if an error has

occurred.

Default Address             An address defined by the USB Specification and used by a USB device when

it is first powered or reset. The default address is 00H.

Default Pipe             The message pipe created by the USB System Software to pass control and

status information between the host and a USB device’s endpoint zero.

Device             A logical or physical entity that performs a function. The actual entity

described depends on the context of the reference. At the lowest level, device

may refer to a single hardware component, as in a memory device. At a

higher level, it may refer to a collection of hardware components that perform

a particular function, such as a USB interface device. At an even higher level,

device may refer to the function performed by an entity attached to the USB;

for example, a data/FAX modem device. Devices may be physical, electrical,

addressable, and logical.

When used as a non-specific reference, a USB device is either a hub or a

function.

Device Address             A seven-bit value representing the address of a device on the USB. The

device address is the default address (00H) when the USB device is first

powered or the device is reset. Devices are assigned a unique device address

by the USB System Software.

출처 : Universal Serial Bus Specification Revision 1.1