Telephone Instruments & Signals Flashcards
The process of conveying information from one place to another
Communication
A long distance communications;
‘tele’ Greek word for distant or afar
Telecommunication
One of the most remarkable devices ever invented
Telephone
Anyone who uses a telephone or data modem on a telephone circuit is part of a global communications network called __
Public telephone network or PTN
The PTN is comprised of several vry large corp. and hundreds of smaller independent companies referred to as _____
Telco
Inventor of telephone
Alexander Graham Bell and Thomas A Watson
Referred to as the Bell Telephone System or “Ma Bell”
AT&T –American Telephone & Telegraph Company
World’s most complicated machine
Bell System
Simplest and most straightforward form of telephone service
POTS – Plain Old Telephone Service
Most fundamental component of a telephone circuit
Local Loop
Provides the means to connect telephone set of the subscriber’s location to the closest telephone office
Subscriber Loop
Telephone office also called ___
end office
local exchange
central office
Enables the subscriber to access the PTN once in the central office
electronic switching system (ESS)
An apparatus for reproducing sound, especially that of the human voice (speech) at a great distance by means of electricity; consisting of transmitting & receiving instruments connected by a line or wire which conveys the electric current
Telephone
Simple analog transceiver designed for converting speech of acoustical signals to electrical signals
Basic Telephone Set
First telephone set that combined a transmitter and receiver into single handheld unit
Butterstamp Telephone (1878)
Introduced by western electric company also called the bell system
Rotary Dial Telephone
Is called a 2500-type telephone circuit
Touch-tone Telephone
Quality of transmission over a telephone connection depends on ___
received volume
Frequency response of the telephone circuit
Degree of the interference
Wires on the local loop
Tip (ground) and Ring (-48 Vdc)
Third wire to be used in a local loop is called ____
Sleeve
A dc voltage is used rather than ac because:
- to prevent power supply hum
- to allow service to continue in the event of a power outage
- people are afraid of ac
the only voltage required for the operation of a standard telephone
48 Vdc
An Electronic oscilllator used to alert the destination party of the incoming calls
Ringer Circuit
