Terms - Blake - LE 1 Flashcards
method of providing high-speed data transmission on twisted-pair telephone loops by
using high-frequency carriers
Asymmetrical Digital Subscriber Line (ADSL)
in ISDN, channels that carry subscriber communication (voice or data or both)
B (bearer) channels
use of bits that normally carry payload information for
other purposes, such as controlling the communication system
bit robbing
addition of bits to a bitstream to compensate for timing
variations
bit stuffing
failure to connect a telephone call because of lack of
system capacity
call blocking
switch in a telephone system that connects to local
subscriber lines
central office
communication system in which a dedicated channel is set up between parties for the duration of the communication
circuit-switched network
use of a separate signaling channel in a
telephone system, so that voice channels do not have to carry signaling information
common-channel signaling
interference between two signals multiplexed into the same channel
crosstalk
in ISDN, a communication channel used for setting up
calls and not for user communication
D (data) channel
signaling using combinations
of two audio tones transmitted on the voice channel
dual-tone multi-frequency (DTMF) dialing
use of optical fiber for telephone connections to
individual customers
fiber-in-the-loop (FITL)
a specialized transformer (or its electronic equivalent) that
allows telephone voice signals to travel in both directions
simultaneously on a single twisted-pair loop
hybrid coil
control signals sent in a voice channel at voice frequencies
in-band signals
control signals using the same channel as a voice signal
in-channel signals
telephone system using
digital local loops for both voice and data, with the codec in the
telephone equipment
integrated services digital network (ISDN)
addition of bits to a digital signal to compensate for
differences in clock rates; informally known as bit stuffing
justification
in a telephone system, the area
controlled by one central office switch
local access and transport area (LATA)
a small data network, usually confined to a building
or cluster of buildings
LAN or local area network
in a telephone system, the wiring from the central office to an individual customer
local loop
in telephone signaling, a control signal that is outside the
voice frequency range
out-of-band
a communication system that works using data
divided into relatively short transmissions called packets; these are routed through the system without requiring a long-term connection between sender and receiver
packet-switched network
place where one telephone network connects to
another
point of presence (POP)
small telephone switch located on customer premises
private branch exchange (PBX)
the ordinary public wireline
phone system
public switched telephone system (PSTN)
in telephony, a signal generated at the central office and
sent to the originating telephone to indicate that the destination telephone is ringing
ringback signal
in telephony, the presence in the receiver of sounds picked up by the transmitter of the same telephone
sidetone
system used in telephony which transmits
all call setup information on a packet-data network that is separate from the voice channels used for telephone conversations
signaling system seven (SS7)
telephone switch that connects only to other switches,
and not to individual customers
tandem office
transmission line carrying many signals, either on multiple
pairs or multiplexed together on a single twisted-pair, coaxial cable, or optical fiber
trunk lines
The single twisted-pair local loop is required to carry both sides of the conversation simultaneously, providing full-duplex communication.
Two-wire System
The rest of the network uses separate transmission
paths for each direction, a topology called a ___
four-wire system
Deliberately unbalancing the circuit allows a small portion of the transmitter signal to reach the receiver, creating a ___ that lets the user know
the line is active and hear what is being transmitted.
sidetone
results in a very slight degradation of voice signal quality; for instance, the
signal-to-noise ratio is reduced by about two decibels
bit robbing
extra bits called ____ which
are added during multiplexing to compensate for differences between the clock rates of the tributaries and the multiplexer
stuff bits
