User Guide ISDN Terminal Adapter MTA128ST-USB

104
MultiModemISDN User Guide
may refer to the function performed by an entity attached to the Universal Serial Bus; for example, a data/FAX modem device. Devices
may be physical, electrical, addressable, and logical. When used as a non-specific reference, a Universal Serial Bus device is either a hub
or a function.
device address: the address of a device on the Universal Serial Bus. The Device Address is the Default Address when the Universal
Serial Bus device is first powered or reset. Hubs and functions are assigned a unique Device Address by Universal Serial Bus software.
device driver—Software that controls how a computer communicates with a device, such as a printer or mouse.
digital data—Information represented by descrete values or conditions (contrast analog data ).
digital PBX—A private branch exchange that operates internally on digital signals. See also exchange .
digital signal— A discrete or discontinuous signal (e.g., a sequence of voltage pulses). Digital devices, such as as a series of electrical
pulses that have discrete jumps rather than gradual changes.
digital transmission—A method of electronic information transmission common among computers and other digital devices. Because a
digital signal may be only
high or low at any given time, noise and distortion can easily be removed from digital transmissions.
digitize—To convert an analog signal to a digital signal.
DIP switch—Pronounced
dip switch . A set of tiny toggle switches, built into a DIP (dual in-line package), used for setting configurable
parameters on a printed circuit board.
DN (directory number)—The phone number assigned to an ISDN TA at subscription time. It is a string of up to 24 characters, consisting of
the valid dialing characters (0-9, *, and #).
driver—A software module that interfaces between the operating system and a specific hardware device (e.g., color monitors, printers,
hard disks, etc.). Also known as a device driver.
DTE (data terminating equipment)—A term used to include any device in a network which generates, stores or displays user information.
DTE is a telecommunications term that usually refers to PCs, terminals, printers, etc.
DTMF (dual-tone multifrequency)—A generic push-button concept made popular by AT&T TouchTone.
DTMF detection—A capability in some fax/data modems that can differentiate between DTMF or fax calling tones. A typical application
would be a program that routes calls to specific communications applications, depending either on the type of call or on a DTMF tone added
to a dialing string.
E
EEPROM (electrically eraseable programmable read-only memory)—A permanent memory chip that can be reprogrammed by the
customer after the manufacturer has set initial values. See also ROM .
EISA (Enhanced Industry Standard Architecture)—Pronounced eesa . The purpose of the EISA bus is to provide a 32-bit bus for faster
throughputs while maintaining backward compatibility with the classic ISA bus architecture.
ET (exchange termination)—The carrier’s local exchange switch. Contrast with LT (loop termination) .
exchange—A unit (public or private) that can consist of one or more central offices established to serve a specified area. An exchange
typically has a single rate of charges (tariffs) that has previously been approved by a regulatory group.
exchange area—A geographical area with a uniform set of charges (tariffs), approved by a regulatory group for telephone services. Calls
between any two points within an exchange area are local calls. See digital PBX and PBX .
F
fax (facsimile)—Refers to the bit-mapped rendition of a graphics-oriented document (fax) or to the electronic transmission of the image
over telephone lines bit-mapped approximation of a graphical document and, therefore, cannot be accurately interpreted according to any
character code.
firmware—Software that is stored in read-only memory (ROM). Unlike random access memory (RAM), ROM can retain its content without
electrical power. Some ROM, known as EEPROM, can be reprogrammed electrically while it is in a device.
foreground—The application program currently running on and in control of the PC screen and keyboard. The area of the screen that
occupies the active window. Compare with background .