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Some telephone technicians used mnemonic phrases, such as red-right-ring-rear, or ring-right-red-rough, to remember that the red wire connects to the right-side post in the wall jack and to the ring on the plug and to the rear lug on main distribution frames. Sometimes rough or ridge was added for jumper wires with a tactile code. [citation needed]
In countries where telephone systems were originally operated by the postal service administrations, the systems were known as post office telephone service as early as 1912 [4] [5] [6] In Australia, New Zealand, and the United Kingdom the telephone system was a government service, under Post Office control, until privatisation in the 1970s and ...
Fixed telephone lines per 100 inhabitants, 1997–2007. Cross section of telephone cable of 1,800 twisted pairs, 1922. A newer telephone cable used to carry telephone lines from several customers. A telephone line or telephone circuit (or just line or circuit industrywide) is a single-user circuit on a telephone communication system. [1]
A telephone switch is the switching equipment of an exchange. A wire center is the area served by a particular switch or central office. A concentrator is a device that concentrates traffic, be it remote or co-located with the switch. An off-hook condition represents a circuit that is in use, e.g., when a telephone call is in progress.
Phantom powering was first used for landline copper wire-based plain old telephone service since the introduction of the rotary dial telephone in 1919. One such application in the telephone system was to provide a DC signalling path around transformer-connected amplifiers such as analogue line transmission systems.
Ringing is a telecommunication signal that causes a bell or other device to alert a telephone subscriber to an incoming telephone call.Historically, this entailed sending a high-voltage alternating current over the telephone line to a customer station which contained an electromagnetic bell.
In many residences, though, the boundary between utility-owned and household-owned cabling is a network interface on an outside wall known as the demarcation point; all wall jacks in the home are part of the household's internal wiring. telephone cord to telephone set base: This connection is generally not regulated, but instead follows de ...
The 20-pair colour code is a colour code used in Australia to identify individual conductors in a kind of electrical telecommunication wiring for indoor use, known as twisted pair cables. The colours are applied to the insulation that covers each conductor. The first colour is chosen from one group of five colours.