Alternating Current (AC) - An electrical current that
reverses direction of flow at regular intervals (e.g. the current
produced by a magneto).
Automatic switching - A system which makes connections
according to the signal from a telephone dial or touchbutton
keyboard. No manual operator is needed to make the connection. The
first automatic systems were electromechanical and depended on
electromagnets to close the connections in the circuit.
Bandwidth - A measure of transmission capacity. The higher a channel's bandwidth, the more information it can carry.
Bucket truck - A truck fitted with a hinged arm ending in
an enclosed platform called a ‘bucket.’ The arm can be raised to let
a worker in the ‘bucket’ service aerial equipment. The bucket unit
is sometimes called a ‘cherry picker.’
Broadband - A transmission medium capable of sending and receiving large amounts of data.
Cable - An assembly of one or more wires in an enveloping
protective sheath. Telephone cable could be hung from poles (aerial
cable) or placed underground running though ducts.
Cable duct - A tube though which a cable passes. Cable
ducts may be underground or they may be tubes installed in a
building to allow cable to run inside walls , under floors or above
Cable vault - A small underground room where workers can
work on cable, entered through a manhole opening.
Catskinner - a worker who operates a Caterpillar tractor
or similar equipment.
Circuit - A circular path in which electrical currents flow.
Circuit board - A card with a printed metal pattern which
serves as an electrical circuit. Other circuit components are
soldered to the board to create a single specialized unit used
within a larger device.
Coaxial cable (coax) - A cable with two conducting layers,
an outer insulated tube and an inner insulated core. The outer layer
provides shielding and conducts noise interference to the ground.
The signal is sent on the inner core. Coaxial cable is excellent for
carrying high frequency signals.
Common battery system - A telephone system where the power
is supplied by batteries in the exchange rather than having
batteries in each telephone. Telephones without large batteries were
more compact and signal quality was improved.
Counter-electromotive force - A force that slows down the
flow of electricity. This could be a problem in telephone
transmission if the wires were not transposed at intervals.
Crossbar switching - A type of line-switching system using
crossbar switches. Vertical or horizontal components are closed by
electromagnets. The connection is not made until dialling is
completed (a common control system).
Direct current (DC) - Electrical current that flows in one
direction (e.g. from a battery).
Drop wire - The wire connecting a subscriber’s telephone
to an aerial cable.
Exchange - A unit where incoming telephone calls are
connected to outgoing lines using switching equipment.
Fibre optic - A fibre cable that transmits data in the form of light pulses.
Ground circuit - A ground circuit travels from the
telephone exchange over a wire and returns to the exchange through
the ground. Early telephone networks using this system needed much
less wire. When electric streetcars using ground circuits were
introduced, the new circuits generated interference noise on the
telephone circuits so they were metallized. In rural networks,
ground circuits were satisfactory for decades.
Handset - A telephone component with a receiver at one end
and a transmitter at the other end, held in the hand when talking on
the telephone. Initially wall telephones had the transmitter mounted
on the wall unit while the receiver was held up to the ear. Models
with a handset are called ‘monophones.’
Innovation - A social and economic process involving the introduction, development and
adaptation of new ideas and marketable products and services.
Insulation - Material that does not conduct electricity,
used in electrical equipment to prevent short circuits or loss of
current (e.g. rubber or plastic coatings on wire).
Insulator - A material that does not conduct electricity
(e.g. glass or ceramic) An telephone insulator is a cup-shaped
fitting with a groove aroune the outside, screwed over a pin on the
crossarm of a telephone pole. The groove was used to attach the
telephone wire to the supporting crossarm.
Invention - A new device, method, or process that has
resulted from study and/or experimentation.
Magnetic induction - Generating a flow of electricity by
the motion of an electrical conducor in a magnetic field. Changing
the strength of the magnetic field without moving the conductor will
also create an electrical current.
Magneto - A small electric generator. A coil of wire
(armature) rotates within a magnetic field, creating an electrical
current by magnetic induction. In early telephones three or five
U-shaped permanent magnets provided the magnetic field and turning a
crank on the side of the telephone made the armature rotate between
the two arms of the magnet.
Microwave - an ultra short radio wave, used in
telecommunications to transmit signals. Microwave towers have
dish-shaped antennae to receive the signals and a transmitting unit
to forward the signal to the next tower.
Morse code - A telegraph code in which dots and dashes
represent letters and numbers.
Multiplexing - Carrying two or more distinct signals
simultaneously on one transmission circuit.
Mutual - A telephone network which was owned and operated
by the subscribers. In Alberta, telephone service in rural areas was
often provided by a mutual before 1950.
NASA - The National Aeronautics and Space Administration
in the United States, reporting to the federal government and
responsible for space exploration.
Network - An organization of interconnected electronic
components, such as computers.
Open wire - Telephone wire that is neither covered by an
insulating layer nor combined with other wires to form a cable.
PABX - Private automatic branch exchange. An exchange
handling calls within a company, hotel, large office, factory etc.
which makes connections automatically, without an operator.
PBX - Private branch exchange. A manual exchange for
private use within a company, hotel, factory, etc. It needs one or
more operators to connect calls within the exchange and to handle
incoming and outgoing calls.
Patent - An exclusive right granted by the government to an inventor
for exclusivity to their invention.
Party line - A telephone line running to two or more
homes. Each subscriber on a party line is assigned a distinct
ringing signal to indicate which incoming calls are for them (e.g. a
long ring followed by two short rings). Party lines are more
economical to install than private lines and were often used in
rural systems where one line could serve up to twenty farms.
Phantom - A method of connecting open wire to create an
additional circuit where two pairs of open wires are already in
place. Three circuits are available for the cost of two.
Photophone - A wireless communication device using light
to transmit signals through air, patented by Alexander Graham Bell.
Receiver - The part of the telephone that receives the
electrical signal and transforms it into sound. It is held up to the
Refractive index - A measurement of the bending of a beam
of light when it passes from material into another and the two
materials have different densities (e.g. light passing from air
through water is bent because air and water have different
Ring and tip (or tip and ring) - The name designating the
two wires of a normal telephone line. The ‘ring’ wire carries the
ringing signal and the ‘tip’ wire carries the voice signal. In early
switchboards the tip wire was connected to the tip of the plug that
was inserted in the jack to make the connection for the call. The
ring wire was attached to a ring of brass that was a few millimetres
behind the tip.
Satellite - A human-made device that orbits the earth and is used for
receiving and transmitting signals.
Selenium (Se) - A non-metallic element, atomic number 34,
atomic weight 78.96. Its electrical resistance varies under the
influence of light. A selenium cell consists of thin strips of
selenium between two metal elctrodes.
Semiconductor - A substance that will conduct electricity,
but does not conduct as well as a metal (e.g. silicon, carbon). The
amount of electricity flowing through a semiconductor can be
Solid state circuit - A circuit using electronic
components (e.g. silicon chips on circuit boards). They replaced
circuits using vacuum tubes and wires.
Spurs (climbing irons) - A pair of metal shanks with a
sharp point at the base, strapped onto the inside of the leg and
under the foot, used for climbing wooden poles.
Step by Step Switching (S x S) - An early automatic
switching system connecting a call as a series of steps
corresponding to each digit dialled by the caller. Step by Step was
an electromechanical system using electromagnets to make the
connection at each step.
Subscriber - A client or customer of a telephone company,
either a person or a business.
Switchboard - a unit which completes telephone circuits to
connect calls. Before switchboards, telephones could only connect
two locations (e.g. Major Walker’s office with his lumberyard a few
miles away). With a switchboard, a caller could be connected to any
telephone in the network.
Switching - Making connections between telephones,
directing the call to the desired destination (can be manual or
Technology - The application of knowledge to develop products or
processes desired by people.
Telecommunications - Communication over a distance through any
type of electronic medium, such as telephone,
television, radio, cable, satellite, and computer.
Telegraph - A system for transmitting messages using an
electrical circuit running through a wire. The message is sent by
using a code of dots and dashes representing each letter and digit.
The telegraph operators opened and closed the circuit to create the
pattern of dots (short interruptions of current) and dashes (longer
intervals) sent through the wire. At the receiving end an
electromagnet operated a sounder and the operator decoded the
pattern of dots and dashes as he listened. Different versions of the
code were developed in Europe and North America.
Toll calls - Long distance calls. The subscriber pays a
toll charge for the call, in addition to the regular monthly fee for
Toll service - Long distance service.
Transistor - A compact electronic device that replaced the
vacuum tube, used to obtain current amplification or switch current
on and off.
Transmitter - The part of the telephone that changes sound
into an electrical signal and transmits it into the telephone
system. It is behind the mouthpiece.
Transposition - A means of controlling
counter-electromotive force developed between two open wires in a
telephone circuit by reversing their position (transposing the
wires) . The wire on the right is placed on the left, and the wire
on the left becomes the wire on the right at intervals.
Wire centre - A term for a telephone exchange building
where the switching equipment is located.
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Heritage Community Foundation and
Telephone Historical Centre All Rights Reserved