Multitech MMH900 User Manual page 192

a conversion chip called a "UART" which
translates between internal parallel and
external serial formats.
Switched Line: In communications, a
physical channel established by dynamically
connecting one or more discreet segments.
This connection lasts for the duration of the
call after which each segment may be used as
part of a different channel. Contrast with
leased line.
Switched Network: A network in which a
temporary connection is established from one
point via one or more segments.
Synchronous Transmission: The transmis-
sion of data which involves sending a group of
characters in a packet. This is a common
method of transmission between computers
on a network or between modems. One or
more synchronous characters are transmitted
to confirm clocking before each packet of data
is transmitted. Compare to Asynchronous
Transmission.
T
T1 Transmission: A standard transmission
speed of 1.544M bps that may be used in its
full bandwidth, or as narrower channels called
"fractional T1" carriers.
Terminal: The screen and keyboard device
used in a centralized computing environment
for interactive data entry. Terminals have no
"box", which is to say they have no file
storage or processing capabilities.
Terminal emulation: This allows a PC to
access a mainframe computer by generating
and accepting data like a "dumb" terminal.
Tone dialing: One of two methods of dialing
a telephone, usually associated with Touch-
Tone® (push button) phones. Compare with
pulse dialing.
Transistor: A semiconductor device used to
amplify a signal, or open and close a circuit.
In digital computers, it functions as an
electronic switch.
Twisted pair wiring: A type of cabling with
one or more pairs of insulated wires wrapped
around each other. An inexpensive wiring
method used for LAN and telephone
applications, also called UTP wiring.
U
UART (Universal Asynchronous Receiver/
Transmitter) (pronounced "you art"): A
chip that transmits and receives data on the
serial port. It converts bytes into serial bits for
transmission, and vice versa, and generates
and strips the start and stop bits appended to
each character.
UTP (unshielded twisted pair): Telephone-
type wiring.
V
V.21: The CCITT modulation standard for
300 bps, full-duplex transmission over dial-up
lines.
V.22: The CCITT modulation standard for
1200 bps, full-duplex transmission over a dial-
up or 2-wire leased line. This is not common
in North America.
V.22bis: The CCITT modulation standard for
2400 bps, full-duplex transmission over a dial-
up or 2-wire leased line.
V.23: The CCITT modulation standard for 75/
1200 bps, half-duplex transmission over dial-
up lines. This is not common in North
America.
V.24: The CCITT hardware interface
specification for interchange circuits between
the DTE and DCE.
V.35: The CCITT hardware interface
specification commonly used by DSU/CSUs
and other high-speed devices.
W
WATS (Wide Area Telephone Service)
(pronounced "watts"): A discounted long-
distance calling plan that allows calls in or out.
The popular 800 numbers are WATS lines in.
The calls are charged to the holder of the 800
number at a discounted rate.
Workstation: Traditionally a workstation has
been a dumb terminal connected to a host.
With the advent of LANs and WANs, PCs that
are connected to a LAN are now called
workstations also, even though they are
capable of independent processing. A
workstation, then, is simply an input/display
device through which a user accesses a
resource.