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🛋 | The number of people returning home this summer has been increasing since 2020.On a day trip while taking measures


The number of people returning home this summer has been increasing since 2020.On a day trip while taking measures

If you write the contents roughly
When asked what to do with family members who could not meet instead of not going home, 46.5% of the respondents answered "telephone (including online)", and there is a tendency to emphasize "conversational communication" such as voice calls and video calls. I heard.

The summer of Corona's disaster has also reached its second time. "This year, I want to go home that didn't come true in 2." "Go play ... → Continue reading

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Wikipedia related words

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Tel(phone,(British: phone) IsvoiceTheElectricalOfsignalI changed it to, transmitted it to a remote place, and returned it to voice again so that I could talk to each othercommunicationmethod[1].


Phone types can be categorized in various ways.For example, based on the signal format in the middle of transmission, it is classified as an analog telephone / digital telephone.

Telephones generally use electric current or radio waves to transmit signals.Optical fiberIt is also widespread to use the light that flows inside.Although it is not very common, technically there is also a "ray phone".A type of spatial optical communication that uses light as a carrier wave.Communication is possible only within the range where they can see each other in a straight line, but high-speed and large-capacity communication is possible.Infrared rays are used in addition to visible light.In recent years, there is also a digital type.

Also, for special purposes, underwater telephonesUltrasoundSome use, and there are analog type and digital type.When performing wireless communication, radio waves are severely attenuated in water, so ultrasonic waves are used instead.


How the phone works

Originally voice電流It was converted into the change of, and it was transmitted to the other party's device as it was, and the current was converted into voice by the other party's device.

With digital telephones that have been popular since the end of the 20th century,modulation,demodulationIncluding procedures such as.Much from the information obtainedBasebandIs further transmitted by a method of encoding on the transmission path (Bandwidth transmission).Although the circuit on the route becomes complicated, there is an advantage that the efficiency of transmitting and receiving information on the power transmission route is improved, and the amount and quality of information are improved.

Telephone line

In the early 19th century, in the early days of the history of the telephone, only two phones were used to connect them with two to four copper wires and leave them connected, always only between the two phones. Simple telephones were often used to make calls.Even in modern times, such simple telephones may be installed in special places where only two telephones are connected by a single covered electric wire and no other telephones can be talked to.

Imagine an early situation in the history of telephones, for example, if you have dozens of homes with telephones in a rural town and you want to make a call between any two of them. ..In such a case, instead of putting a wire between all the phones,HubCreate one place (that is, a place called "telephone office"), lay the electric wire connecting the telephone office and each telephone, and extend from two telephones to talk in the telephone office. If the method of connecting the electric wires to the electric wires is adopted, the total length (total length) of the electric wires can be shortened. At the end of the 1th century and the first half of the 2th century, switching of wire interconnections was mainly done manually by humans.The work of connecting telephone wires to each other and switching the connection is called "exchange work", and the person who does it is called "replacement work".Operator"Or"Telephone operatorI said.And the "telephone office" has a switchboard, which is electrical technology.Patch panelThe method of electrically connecting telephones to each other using the above is widely adopted because it allows quick interconnection and easy switching of connections.For example, if "Mr. 20" tells the operator "I want to make a call with Mr. 35", the operator prepares one cable and connects the terminals at both ends to "1" on the patch panel. All you have to do is insert it into the hole labeled "No." and the hole labeled "No. 20".

After that, a method was developed to mechanically convey the call destination by pulse transmission of the telephone instead of telling the operator by voice, and a machine was also made to automatically perform the interconnection and reconnection work that was done manually (Telephone exchange), It gradually spread.

In modern times, the landline system is not a phone-to-phone system, only when making a call.Telephone exchangeConnect multiple phones withLineMethod to secure (Circuit switching) Is taken[2], Is the explanation.

Modern telephone lines are huge, interconnected worldwide by automatic exchangesTelephone networkIs formed.Fixed-line phone,Mobile phone,Satellite phone,IP phoneA wide variety of telephone interconnections, etc.Wireless callIt is also possible to make a call to.Not only for human voice calls, but also in the 1990sインターネットToDial-up connectionSuch asComputer networkIt has also come to be used.


A phone (technically speaking) isElectromagnetic inductionIt is a device for converting voice into an electrical signal (sending) and (conversely, receiving) an electrical signal into voice using the principle of.[3].

Focusing on the relationship with the operation of the exchange, it can be classified as follows.

  • Dial pulseTelephone (rotary dial telephone).Each time you put your finger in the hole of the dial according to the number, turn it to the stopper, and pull out your finger, an electric pulse is transmitted the corresponding number of times. No new products have appeared since the beginning of the 21st century.
  • Push button phone: DTMFA telephone that makes a phone number with.
  • Answering machine: A phone or service that records incoming calls when you are away.
  • Cordless phone: The userbase stationRadiotelephone system to install.

Also, devices that send and receive images using telephone linesfacsimile (FAX)[4]..facsimile·Copier-Image scannerEtc. in one housingデ ジ タ ルoffice supply TheMFPCalled.

At the same time as voiceMovieWhat made it possible to sendVideophoneThat.

Public phone

Public phoneIs installed on the streets and public transportation vehicles, etc.coin,token(Telephone coin),prepaid card,Credit cardA telephone that can be used for such purposes.

Landline and mobile phones

A wired telephone that is fixedly installed in a building such as a home or office and pays a monthly call charge.Fixed-line phoneThat.

  • Single phone: Subscriber lineIs occupied by one subscriber.
  • Shared phone: Multiple subscribers share the subscriber line in order to effectively utilize the line of the telephone exchange.

Mobile phones appeared in the old car phones and laterMobile phoneAnd so on.For mobile phones, connect the station and line with radio wavesWireless phoneOr connect the line using an artificial satelliteSatellite phoneand so on.

Call type

Local call
Unit charge area (MA) A landline phone that arrives and departs internally.Also called a local phone.
Toll call
Calls outside the local telephone area (domestic).Toll phone.
international call
Make a phone call abroad.International call.
A call in which the calling party makes a call, the called party obtains the calling party's telephone number, then the line is temporarily opened, and the called party calls back the calling party.

Telephone operation and management

If the service expands, it is essential to invest in installing the necessary facilities, but if there is time to recover the investment, it will not be possible to provide the service to all users at once, resulting in a stagnation.However, unlike the mail, there is a law in the telephone that if the number of users is increased, the cost borne by the individual will gradually decrease.In other words, as the ground contact area of ​​the telephone line of one operator increases, the burden on the user will be reduced to a certain level.At the same time, if the operator collapses due to excessive competition, there will be disadvantages for users.

As a result, the telephone business is a government-owned company that pursues public interest in terms of eliminating the stagnation rate and the cost of public services.BT groupWhether it is the British method before its appearance) or the latter is privatized to some extent at the discretion of the administration after separating the local area and the backbone network (American before the division).AT&TThe country was forced to make a choice (which played this role), and after the defeat, Japan decided to make the form of the business entity a public corporation. 1980sCommunication liberalizationThis controversy will reignite inJapanInDenden Public CorporationFor the process of privatization, Teruyuki Inoue, "Study of the process of privatization of electricity and electricity" (Elk) ISBN-978 4434001475) Is detailed.With the advent of the Internet era, new developments have opened up again.


[How to use footnotes]


  1. ^ Shogakukan "Encyclopedia Nipponica" "Telephone"
  2. ^ Isao Taniguchi, "Introduction to Illustrated Basics and Mechanisms of the Latest Communication, Common Knowledge of Communication, Second Edition," Shuwa System, 2, p. 2007
  3. ^ Isao Taniguchi, "Introduction to Illustrated Basics and Mechanisms of the Latest Communication, Common Knowledge of Communication, Second Edition," Shuwa System, 2, p. 2007
  4. ^ Isao Taniguchi, "Introduction to Illustrated Basics and Mechanisms of the Latest Communication, Common Knowledge of Communication, Second Edition," Shuwa System, 2, p. 2007

Related item

Telephone mechanism / type / interconnection

Phone Number

Phone symbol

This section includes some computers andBrowsing softwareContains characters (phone marks) that cannot be displayed with(Details).

The telephone symbols are "☎", "☏", "✆", "℡" (TEL).

Qualifications / personnel

  • Chief Telecommunications Engineer - for businessTelecommunicationsSupervision of equipment construction, maintenance and managementQualifications/Licenses.
  • Person in charge of construction --Qualification to carry out and supervise the construction of terminal equipment.Commonly known as "constructor" and "instructor".
  • Radio engineer --When certain requirements are met when relaying a call using a wireless device.
  • Operator --People who connected the route to the other party before the spread of automatic exchanges.Even now, in large companies and organizations that have representative numbers and major representative numbers, there are mainly full-time employees in the general affairs department who send calls to the representative number to the department in charge according to the content.


外部 リンク

Postal Museum: After the Communications Museum closed due to the Great East Japan Earthquake, the part operated by the Tsushinbunka Association moved to Skytree.

NTT History Center of Technologies: After the Communications Museum was closed due to the Great East Japan Earthquake, some of the exhibits that were operated by NTT East were exhibited.


Online(British: online) Is

  • Computer networkso,nodeIndicates a state in which is connected to the network and can enjoy the service.The antonym isoff-line(Offline).
  • Conversations, meetings, exchanges, etc. between people using communication equipment.

National Institute for Japanese Language The"Foreign language" paraphrase proposalAlthough it was called "line connection", it is currently withdrawn.[Source required]


A node is online when it is connected to another node and can be serviced. With the terminalhost,clientとserverThere are various types of connection such as client and client.

bank OfAccount system,JR OfMars systemIllustrated inTrainな どTransportationSeat reservation system, connected to the serveronline gameAs their ownprotocolTo connect to a network hostComputer systemIndicates a serviceable state.

Peripheral devices, recording media, etc. may be connected to the computer and can be used normally, but this is strictly a misuse. (""SD cardIs online "etc.)

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