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Alberta Online Encyclopedia
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Alberta's Telephone Heritage
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Glossary

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 ceilings.

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 ear.

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 densities).

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 precisely controlled.

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 automatic).

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 local service.

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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