switch-hook operation
11Public switched telephone network — The public switched telephone network (PSTN) is the network of the world s public circuit switched telephone networks. It consists of telephone lines, fiber optic cables, microwave transmission links, cellular networks, communications satellites …
12Telephone — The telephone (from the el. τῆλε, tēle , far and φωνή, phōnē , voice ) is a telecommunications device that is used to transmit and receive sound (most commonly speech), usually two people conversing but occasionally three or more. It is one of… …
13Telephone exchange — A telephone operator manually connecting calls with cord pairs at a telephone switchboard. In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls. A central… …
14Ceiling fan — A ceiling fan is a fan, usually electrically powered, suspended from the ceiling of a room, that uses hub mounted rotating paddles to circulate air. Casablanca Fan Co. ceiling fan from the early 1980s. A ceiling fan rotates much mo …
15Phreaking — is a slang term coined to describe the activity of a subculture of people who study, experiment with, or explore telecommunication systems, like equipment and systems connected to public telephone networks. The term phreak is a portmanteau of the …
16Ringdown — Ringdown: In telephony, a method of signaling an operator in which telephone ringing current is sent over the line to operate a lamp or cause the operation of a self locking relay known as a drop . Ringdown (a) is used in manual operation, as… …
17History of the telephone — The history of the telephone chronicles the development of electrical technology that enabled bidirectional human speech conversations over distances farther than a person could shout.Telephone prehistoryMechanical devicesBefore the invention of… …
18Right- and left-hand traffic —   countries with right hand traffic …
19History of the Netherlands — This article is part of a series Early History …
20Fairchild C-123 Provider — C 123 Provider A United States Coast Guard HC 123B Provider from CGAS Miami. Role …
