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Remote controls are used any time a two-way radio base station is located away from the desk or office where communication originates. For example, a dispatch center for taxicabs may have an office downtown but have a base station on a distant mountain top. A Tone remote, also known as an EIA Tone remote, is a signaling system used to operate a two-way radio base station by some form of remote control.〔EIA is the abbreviation for ''Electronics Industry Association'', an industry organization that worked to create a standard format for tone remote controls.〕〔Any two-way radio remote control console manual will explain the basic principles of the respective equipment. One example is the 1970s-era, ''Maintenance Manual: Deskon II Remote Control Unit for Standard and GE Mark V Trunked Mobile Radio Desk Top and Wall Mount'', part number LBI30968B, (Lynchburg, Virginia: General Electric Mobile Radio, unknown year). This GE manual covers tone- and DC-remotes.〕〔To confirm the use of the phrase "tone remote" as accurate in describing this type of device, please see US Patent and Trademark Office patent ID 6950653, "Scanning tone remote adapter for land-mobile radio dispatch for use with dispersed dispatch stations." The article does not describe this tone remote but confirms the use of the phrase to describe this system of signaling.〕 A tone remote may be a stand-alone desktop device in a telephone housing with a speaker where the dial would have been located. It may look like a desk top base station. Or, it may be an integral part of a computer-based console system with touch-screens in a dispatch center. ==History== The first two-way radio remote controls utilized a harness of wires extending speaker, microphone, and controls for options such as channel selection or CTCSS switches. This limited a base station to being within tens to hundreds of feet from the user's workstation. Early systems often had volume unit meters, clocks, and switchboard keys.〔A picture of one example is shown in Crane, Bob, "Highway Patrol Radio Communications Development," ''California Association of Highway Patrolmen Golden Chronicle 1920-1970'', (Sacramento, California: California Association of Highway Patrolmen, 1970,) pp. 71.〕 1960s two-way radio remote control consoles used direct current loops. Users would run ordinary telephone wiring from the remote consoles to the radio base station chassis.〔One example describing DC-remotes is found in, "Section 8.4, Console Electronics" in ''Trunked Radio System Request For Proposals'', (Oklahoma City, Oklahoma: Public Safety Capital Projects Office, Oklahoma City Municipal Facilities Authority, 2000) pp. 157. Unlike tone remotes, there are no default currents that map to specific functions. Service manuals for a specific type of equipment will reveal how many functions are available and what currents and polarities actuate a specific function. These may be modified from one system to another.〕 In some cases, the base station was located at the same address as the control console. In other cases, the base station was located at a distant site. For distant sites, a dry pair of telephone wires called a ''DC loop'', ''private line-'' or ''RTO circuit'' (Radio Telephone Operation) was leased from the telephone company. Older burglar alarms used the same type of DC wiring from subscriber location to the alarm office. As pair gain electronics and point-to-point microwave radio links came into widespread use throughout the public switched telephone network, telephone companies filed tariffs to eliminate their past responsibility of providing leased circuits with direct current continuity. If the base station were located across town in an area served by a different telephone exchange, the only available circuits reaching the distant exchange might be a single voice-grade channel in a D-4 channel bank on a DS-1 or a single microwave radio baseband channel. Tone remotes became necessary with the wide use of telephone carrier or multiplexing equipment. They require only a voice-grade audio path with roughly flat equalization from 300-3,000 Hz. A circuit that could pass audio in both directions could be used for remote control. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Tone remote」の詳細全文を読む スポンサード リンク
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