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140-1105: An amateur radio repeater is an electronic device that receives a weak or low-level amateur radio signal and retransmits it at a higher level or higher power, so that the signal can cover longer distances without degradation. Many repeaters are located on hilltops or on tall buildings as the higher location increases their coverage area, sometimes referred to as the radio horizon , or "footprint". Amateur radio repeaters are similar in concept to those used by public safety entities (police, fire department, etc.), businesses, government, military, and more. Amateur radio repeaters may even use commercially packaged repeater systems that have been adjusted to operate within amateur radio frequency bands, but more often amateur repeaters are assembled from receivers, transmitters, controllers, power supplies, antennas, and other components, from various sources. In amateur radio , repeaters are typically maintained by individual hobbyists or local groups of amateur radio operators . Many repeaters are provided openly to other amateur radio operators and typically not used as

280-440: A POTS / PSTN telephone line to allow users to make telephone calls from their keypad-equipped radios. These advanced services may be limited to members of the group or club that maintains the repeater. Many amateur radio repeaters typically have a tone access control ( CTCSS , also called CG or PL tone ) implemented to prevent them from being keyed-up (operated) accidentally by interference from other radio signals. A few use

420-466: A call sign on the air to legally identify the operator or station. In some countries, the call sign assigned to the station must always be used, whereas in other countries, the call sign of either the operator or the station may be used. In certain jurisdictions, an operator may also select a "vanity" call sign although these must also conform to the issuing government's allocation and structure used for Amateur Radio call signs. Some jurisdictions require

560-606: A disruptive technology that is rapidly replacing traditional telephone network infrastructure. By January 2005, up to 10% of telephone subscribers in Japan and South Korea had switched to this digital telephone service. A January 2005 Newsweek article suggested that Internet telephony may be "the next big thing." The technology has spawned a new industry comprising many VoIP companies that offer services to consumers and businesses . The reported global VoIP market in October 2021

700-412: A phone , is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound , typically and most efficiently the human voice , into electronic signals that are transmitted via cables and other communication channels to another telephone which reproduces the sound to the receiving user. The term

840-685: A remote base station by a single user or group. In some areas multiple repeaters are linked together to form a wide-coverage network, such as the linked system provided by the Independent Repeater Association which covers most of western Michigan, or the Western Intertie Network System ("WINsystem") that now covers a great deal of California, and is in 17 other states, including Hawaii, along with parts of four other countries, Australia, Canada, Great Britain and Japan. Repeaters are found mainly in

980-483: A subscriber , who had to arrange for a telegraph contractor to construct a line between them, for example, between a home and a shop. Users who wanted the ability to speak to several different locations would need to obtain and set up three or four pairs of telephones. Western Union , already using telegraph exchanges, quickly extended the principle to its telephones in New York City and San Francisco , and Bell

1120-437: A water microphone , some had a metal diaphragm that induced current in an electromagnet wound around a permanent magnet, and some were dynamic – their diaphragm vibrated a coil of wire in the field of a permanent magnet or the coil vibrated the diaphragm. The sound-powered dynamic variants survived in small numbers through the 20th century in military and maritime applications, where its ability to create its own electrical power

1260-479: A DC transformer which plugs into a wall AC power outlet. A mobile phone or cellphone or hand phone is a handheld telephone which connects via radio transmissions to a cellular telephone network . The cellular network consists of a network of ground based transmitter/receiver stations with antennas – which are usually located on towers or on buildings – and infrastructure connecting to land-based telephone lines. Analog cellular networks first appeared in 1979, with

1400-456: A US citizen may operate under reciprocal agreements in Canada, but not a non-US citizen holding a US license. Many people start their involvement in amateur radio on social media or by finding a local club. Clubs often provide information about licensing, local operating practices, and technical advice. Newcomers also often study independently by purchasing books or other materials, sometimes with

1540-471: A band's article for specifics. [ w ] HF allocation created at the 1979 World Administrative Radio Conference . These are commonly called the " WARC bands ". [ x ] This is not mentioned in the ITU 's Table of Frequency Allocations , but many individual administrations have commonly adopted this allocation under "Article 4.4" . [ y ] This includes a currently active footnote allocation mentioned in

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1680-405: A beep or chirp tone to signal that the timeout timer has reset. Conventional repeaters, also known as in-band or same-band repeaters, retransmit signals within the same frequency band , and they only repeat signals using a particular modulation scheme, predominately FM . Standard repeaters require either the use of two antennas (one each for transmitter and receiver) or a duplexer to isolate

1820-441: A club or organization for a period of time before a higher class of license can be acquired. A reciprocal licensing agreement between two countries allows bearers of an amateur radio license in one country under certain conditions to legally operate an amateur radio station in the other country without having to obtain an amateur radio license from the country being visited, or the bearer of a valid license in one country can receive

1960-464: A club or organization generally requires that an individual with a current and valid amateur radio license who is in good standing with the telecommunications authority assumes responsibility for any operations conducted under the club license or club call sign. A few countries may issue special licenses to novices or beginners that do not assign the individual a call sign but instead require the newly licensed individual to operate from stations licensed to

2100-553: A codec in the user radio and along with the encoded audio, also send and receive user number and destination information so one can talk to another specific user or a Talk Group. Two such worldwide networks are DMR-MARC and Brandmeister. For example, a simplex gateway may be used to link a simplex repeater into a repeater network via the Internet. [ v ] All allocations are subject to variation by country. For simplicity, only common allocations found internationally are listed. See

2240-439: A computer softphone application, utilizing the microphone and headset devices of a personal computer or smartphone. While traditional analog telephones are typically powered from the central office through the telephone line, digital telephones require a local power supply. Internet-based digital service also requires special provisions to provide the service location to the emergency services when an emergency telephone number

2380-862: A country. For example, the peak envelope power limits for the highest available license classes in a few selected countries are: 2.25  kW in Canada; 1.5 kW in the United States; 1.0 kW in Belgium, Luxembourg , Switzerland, South Africa and New Zealand; 750 W in Germany; 500 W in Italy; 400 W in Australia, India, and the United Kingdom; and 150 W in Oman . Telephone A telephone , colloquially referred to as

2520-556: A digital code system called DCS , DCG or DPL (a Motorola trademark). In the UK most repeaters also respond to a short burst of 1750 Hz tone to open the repeater. In many communities, a repeater has become a major on-the-air gathering spot for the local amateur radio community, especially during "drive time" (the morning or afternoon commuting time). In the evenings local public service nets may be heard on these systems and many repeaters are used by weather spotters . In an emergency or

2660-475: A disaster a repeater can sometimes help to provide needed communications between areas that could not otherwise communicate. Until cellular telephones became popular, it was common for community repeaters to have "drive time" monitoring stations so that mobile amateurs could call in traffic accidents via the repeater to the monitoring station who could relay it to the local police agencies via telephone. Systems with autopatches frequently had (and still have) most of

2800-413: A display for caller ID . In addition, answering machine function may be built in. The cordless handset contains a rechargeable battery , which the base station recharges when the handset rests in its cradle. Muilt-handset systems generally also have additional charging stands. A cordless telephone typically requires a constant electricity supply to power the base station and charger units by means of

2940-430: A dynamic transmitter or by the powering of a transmitter with a local battery. One of the jobs of outside plant personnel was to visit each telephone periodically to inspect the battery. During the 20th century, telephones powered from the telephone exchange over the same wires that carried the voice signals became common. Early telephones used a single wire for the subscriber's line, with ground return used to complete

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3080-571: A fee to obtain such a vanity call sign; in others, such as the UK, a fee is not required and the vanity call sign may be selected when the license is applied for. The FCC in the U.S. discontinued its fee for vanity call sign applications in September 2015, but replaced it as $ 35 in 2022. Call sign structure as prescribed by the ITU consists of three parts which break down as follows, using the call sign ZS1NAT as an example: Many countries do not follow

3220-561: A given period of time. In addition to contests, a number of amateur radio operating award schemes exist, sometimes suffixed with "on the Air", such as Summits on the Air , Islands on the Air, Worked All States and Jamboree on the Air . Amateur radio operators may also act as citizen scientists for propagation research and atmospheric science . Radio transmission permits are closely controlled by nations' governments because radio waves propagate beyond national boundaries, and therefore radio

3360-417: A handle with the receiver and transmitter attached, now called a handset , separate from the cradle base that housed the magneto crank and other parts. They were larger than the "candlestick" and more popular. Disadvantages of single-wire operation such as crosstalk and hum from nearby AC power wires had already led to the use of twisted pairs and, for long-distance telephones, four-wire circuits . Users at

3500-457: A national licensing process and may instead require prospective amateur radio operators to take the licensing examinations of a foreign country. In countries with the largest numbers of amateur radio licensees, such as Japan, the United States, Thailand, Canada, and most of the countries in Europe, there are frequent license examinations opportunities in major cities. Granting a separate license to

3640-432: A nuisance. The use of "ham" meaning "amateurish or unskilled" survives today sparsely in other disciplines (e.g. "ham actor"). The amateur radio community subsequently began to reclaim the word as a label of pride, and by the mid-20th century it had lost its pejorative meaning. Although not an acronym or initialism, it is often written as "HAM" in capital letters. The many facets of amateur radio attract practitioners with

3780-472: A number after to indicate the political region; prefix CY indicates geographic islands. Prefix VA1 or VE1 is Nova Scotia , VA2 / VE2 is Quebec , VA3 / VE3 is Ontario , VA4 / VE4 is Manitoba , VA5 / VE5 is Saskatchewan , VA6 / VE6 is Alberta , VA7 / VE7 is British Columbia , VE8 is the Northwest Territories , VE9 is New Brunswick , VY0

3920-409: A pool of at least 350. To pass, 26 of the 35 questions must be answered correctly. The Extra Class exam has 50 multiple choice questions (drawn randomly from a pool of at least 500), 37 of which must be answered correctly. The tests cover regulations, customs, and technical knowledge, such as FCC provisions, operating practices, advanced electronics theory, radio equipment design, and safety. Morse Code

4060-432: A repeater was on "22/82"—today they will most often be told "682 down". The 6 refers to the last digit of 146 MHz, so that the display will read "146.82" (the output frequency), and the radio is set to transmit "down" 600 kHz on 146.22 MHz. Another way of describing a repeater frequency pair is to give the repeater's output frequency, along with the direction of offset ("+" or "plus" for an input frequency above

4200-478: A repeater. One type of SSTV repeater is activated by a station sending it a 1,750 Hz tone. The repeater sends K in morse code to confirm its activation, after which the station must start sending a picture within about 10 seconds. After reception, the received image is transmitted on the repeater's operation frequency. Another type is activated by the SSTV vertical synchronization signal (VIS code). Depending on

4340-483: A satellite may be of any type; the key distinction is that they are in orbit around the Earth, rather than terrestrial in nature. The three most common types of OSCARs are linear transponders, cross-band FM repeaters, and digipeaters (also referred to as pacsats). Amateur transponder repeaters are most commonly used on amateur satellites . A specified band of frequencies, usually having a bandwidth of 20 to 800 kHz

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4480-591: A satellite phone is that it can be used in such regions where local terrestrial communication infrastructures, such as landline and cellular networks, are not available. Satellite phones are popular on expeditions into remote locations, hunting, fishing, maritime sector, humanitarian missions, business trips, and mining in hard-to-reach areas, where there is no reliable cellular service. Satellite telephones rarely get disrupted by natural disasters on Earth or human actions such as war, so they have proven to be dependable communication tools in emergency situations, when

4620-436: A separate license and a call sign in another country, both of which have a mutually-agreed reciprocal licensing approvals. Reciprocal licensing requirements vary from country to country. Some countries have bilateral or multilateral reciprocal operating agreements allowing hams to operate within their borders with a single set of requirements. Some countries lack reciprocal licensing systems. Others use international bodies such as

4760-404: A short distance from the base station. Base stations include a radio transceiver which enables full-duplex, outgoing and incoming signals and speech with the handsets. The base station often includes a microphone, audio amplifier , and a loudspeaker to enable hands-free speakerphone conversations, without needing to use a handset. The base station may also have a numeric keypad for dialing, and

4900-513: A signal, on different frequency, as they receive it. Instead, they operate in a store-and-forward manner, by receiving and then retransmitting on the same frequency after a short delay. These systems may not be legally classified as "repeaters", depending on the definition set by a country's regulator. For example, in the US, the FCC defines a repeater as an "amateur station that simultaneously retransmits

5040-429: A single molded plastic handle, which when not in use was secured in a cradle in the base unit. The circuit diagram of the model 202 shows the direct connection of the transmitter to the line, while the receiver was inductively coupled. In local battery configurations, when the local loop was too long to provide sufficient current from the exchange, the transmitter was powered by a local battery and inductively coupled, while

5180-428: A telephone are a microphone ( transmitter ) to speak into and an earphone ( receiver ) which reproduces the voice at a distant location. The receiver and transmitter are usually built into a handset which is held up to the ear and mouth during conversation. The transmitter converts the sound waves to electrical signals which are sent through the telecommunications system to the receiving telephone, which converts

5320-404: A unique identifying call sign , which must be used in all transmissions. Amateur operators must hold an amateur radio license which is obtained by passing a government test demonstrating adequate technical radio knowledge and legal knowledge of the host government's radio regulations. Radio amateurs are limited to a specific set of frequency bands, the amateur radio bands, allocated throughout

5460-551: A wide range of interests. Many amateurs begin with a fascination with radio communication and then combine other personal interests to make pursuit of the hobby rewarding. Some of the focal areas amateurs pursue include radio contesting , radio propagation study, public service communication , technical experimentation , and computer networking . Hobbyist radio enthusiasts employ a variety of transmission methods for interaction . The primary modes for vocal communications are frequency modulation (FM) and single sideband (SSB). FM

5600-514: A wired interface, such as USB or Lightning connectors. Smartphones, being able to run apps , have vastly expanded functionality compared to previous mobile phones. Having internet access and built in cameras, smartphones have made video calling readily accessible via IP connections. Smartphones also have access to a large number of web services and web apps, giving them functionality similar to traditional computers, although smartphones are often limited by their relatively small screen size and

5740-717: A year in the national capital and can be inordinately bureaucratic (for example in India) or challenging because some amateurs must undergo difficult security approval (as in Iran ). Currently, only Yemen and North Korea do not issue amateur radio licenses to their citizens. Some developing countries, especially those in Africa, Asia, and Latin America , require the payment of annual license fees that can be prohibitively expensive for most of their citizens. A few small countries may not have

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5880-411: Is Nunavut , VY1 is Yukon , VY2 is Prince Edward Island , VO1 is Newfoundland , and VO2 is Labrador . CY is for amateurs operating from Sable Island (CY0) or St. Paul Island (CY9). Special permission is required to access either of these: from Parks Canada for Sable and Coast Guard for St. Paul. The last two or three letters of the call signs are typically the operator's choice (upon completing

6020-399: Is an amateur radio repeater station that relays slow-scan television signals. A typical SSTV repeater is equipped with a HF or VHF transceiver and a computer with a sound card , which serves as a demodulator/modulator of SSTV signals. SSTV repeaters are used by amateur radio operators for exchanging pictures. If two stations cannot copy each other, they can still communicate through

6160-410: Is assigned by a local frequency coordinating council. In the days of crystal-controlled radios, these pairs were identified by the last portion of the transmit (Input) frequency followed by the last portion of the receive (Output) frequency that the ham would put into the radio. Thus "three-four nine-four" (34/94) meant that hams would transmit on 146.34 MHz and listen on 146.94 MHz (while

6300-400: Is called. A cordless telephone or portable telephone consists of a base station unit and one or more portable cordless handsets . The base station connects to a telephone line, or provides service by voice over IP (VOIP). The handset communicates with the base station via radio frequency signals. A handset's operational range is limited, usually to within the same building or within

6440-529: Is derived from Ancient Greek : τῆλε , romanized :  tēle , lit.   'far' and φωνή ( phōnē , voice ), together meaning distant voice . In 1876, Alexander Graham Bell was the first to be granted a United States patent for a device that produced clearly intelligible replication of the human voice at a second device. This instrument was further developed by many others, and became rapidly indispensable in business , government , and in households . The essential elements of

6580-604: Is in the Turks and Caicos Islands, VP6xxx is on Pitcairn Island, VP8xxx is in the Falklands, and VP9xxx is in Bermuda. Online callbooks or call sign databases can be browsed or searched to find out who holds a specific call sign. An example of an online callbook is QRZ.com . Non-exhaustive lists of famous people who hold or have held amateur radio call signs have also been compiled and published. Many jurisdictions (but not in

6720-458: Is necessary. A repeater controller can be a hardware solution or even be implemented in software. Repeaters typically have a timer to cut off retransmission of a signal that goes too long. Repeaters operated by groups with an emphasis on emergency communications often limit each transmission to 30 seconds, while others may allow three minutes or even longer. The timer restarts after a short pause following each transmission, and many systems feature

6860-471: Is no longer tested in the U.S. Once the exam is passed, the FCC issues an Amateur Radio license which is valid for ten years. Studying for the exam is made easier because the entire question pools for all license classes are posted in advance. The question pools are updated every four years by the National Conference of VECs. Prospective amateur radio operators are examined on understanding of

7000-560: Is of international concern. Both the requirements for and privileges granted to a licensee vary from country to country, but generally follow the international regulations and standards established by the International Telecommunication Union and World Radio Conferences . All countries that license citizens to use amateur radio require operators to display knowledge and understanding of key concepts, usually by passing an exam. The licenses grant hams

7140-522: Is recognized for its superior audio quality, whereas SSB is more efficient for long-range communication under limited bandwidth conditions. Radiotelegraphy using Morse code , also known as "CW" from " continuous wave ", is the wireless extension of landline (wired) telegraphy developed by Samuel Morse and dates to the earliest days of radio. Although computer-based (digital) modes and methods have largely replaced CW for commercial and military applications, many amateur radio operators still enjoy using

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7280-435: Is repeated from one band to another. Transponders are not mode specific and typically no demodulation occurs. Any signal with a bandwidth narrower than the transponder's pass-band will be repeated; however, for technical reasons, use of modes other than SSB and CW are discouraged. Transponders may be inverting or non-inverting. An example of an inverting transponder would be a 70cm to 2m transponder which receives on

7420-419: Is similar to Voice over IP (VoIP), but augments two-way radio communications rather than telephone calls. EchoLink using VoIP technology has enabled amateurs to communicate through local Internet-connected repeaters and radio nodes, while IRLP has allowed the linking of repeaters to provide greater coverage area. Automatic link establishment (ALE) has enabled continuous amateur radio networks to operate on

7560-692: Is the Wireless Institute of Australia , formed in 1910; other notable societies are the Radio Society of Great Britain , the American Radio Relay League , Radio Amateurs of Canada , Bangladesh NGOs Network for Radio and Communication , the New Zealand Association of Radio Transmitters and South African Radio League . ( See Category:Amateur radio organizations ) An amateur radio operator uses

7700-606: Is the address of the call recipient's telephone in the telecommunications system, but other methods existed in the early history of the telephone. The first telephones were directly connected to each other from one customer's office or residence to another customer's location. Being impractical beyond just a few customers, these systems were quickly replaced by manually operated centrally located switchboards . These exchanges were soon connected together, eventually forming an automated, worldwide public switched telephone network . For greater mobility, various radio systems were developed in

7840-684: Is typically found in the 70 cm (420–450 MHz) wavelength range, though there is also limited use on 33 cm (902–928 MHz), 23 cm (1240–1300 MHz) and shorter. These requirements also effectively limit the signal range to between 20 and 60 miles (30–100 km). Linked repeater systems, however, can allow transmissions of VHF and higher frequencies across hundreds of miles. Repeaters are usually located on heights of land or on tall structures, and allow operators to communicate over hundreds of miles using hand-held or mobile transceivers . Repeaters can also be linked together by using other amateur radio bands , landline , or

7980-415: Is used for digital ATV, due to narrow bandwidth needs and high loss tolerances. These DATV repeaters are more prevalent in Europe currently, partially because of the availability of DVB-S equipment. In addition, amateur radio satellites have been launched with the specific purpose of operating as space-borne amateur repeaters. The worldwide amateur satellite organization AMSAT designs and builds many of

8120-619: Is valid only in the country where it is issued or in another country that has a reciprocal licensing agreement with the issuing country. In some countries, an amateur radio license is necessary in order to purchase or possess amateur radio equipment. Amateur radio licensing in the United States exemplifies the way in which some countries award different levels of amateur radio licenses based on technical knowledge: three sequential levels of licensing exams (Technician Class, General Class, and Amateur Extra Class) are currently offered, which allow operators who pass them access to larger portions of

8260-428: The 33 or 23 cm band and output on 421.25 MHz or, sometimes, 426.25 MHz (within the 70 cm band ). These output frequencies happen to be the same as standard cable television channels 57 and 58, meaning that anyone with a cable-ready analog NTSC TV can tune them in without special equipment. There are also digital amateur TV repeaters that retransmit digital video signals. Frequently DVB-S modulation

8400-563: The Central Scotland FM Group and the Scottish Borders Repeater Group . The most basic repeater consists of an FM receiver on one frequency and an FM transmitter on another frequency usually in the same radio band, connected together so that when the receiver picks up a signal, the transmitter is keyed and rebroadcasts whatever is heard. In order to run the repeater a repeater controller

8540-611: The Earth instead of terrestrial cell sites , as cellphones do. Therefore, they can work in most geographic locations on the Earth's surface, as long as open sky and the line-of-sight between the phone and the satellite is provided. Depending on the architecture of a particular system, coverage may include the entire Earth or only specific regions. Satellite phones provide similar functionality to terrestrial mobile telephones; voice calling , text messaging , and low-bandwidth Internet access are supported through most systems. The advantage of

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8680-724: The Internet . Amateur radio satellites can be accessed, some using a hand-held transceiver ( HT ), even, at times, using the factory "rubber duck" antenna. Hams also use the moon , the aurora borealis , and the ionized trails of meteors as reflectors of radio waves. Hams can also contact the International Space Station (ISS) because many astronauts are licensed as amateur radio operators. Amateur radio operators use their amateur radio station to make contacts with individual hams as well as participate in round-table discussion groups or "rag chew sessions" on

8820-548: The Internet . Amateur radio is officially represented and coordinated by the International Amateur Radio Union (IARU), which is organized in three regions and has as its members the national amateur radio societies which exist in most countries. According to an estimate made in 2011 by the American Radio Relay League (the American national amateur radio society), two million people throughout

8960-572: The Reis telephone , in c. 1860. His device appears to be the first device based on the conversion of sound into electrical impulses. The term telephone was adopted into the vocabulary of many languages. It is derived from the Greek : τῆλε , tēle , "far" and φωνή, phōnē , "voice", together meaning "distant voice". Credit for the invention of the electric telephone is frequently disputed. As with other influential inventions such as radio , television ,

9100-533: The VHF 6-meter (50–54 MHz), 2-meter (144–148 MHz), 1.25-meter band (1 1 ⁄ 4 meters) (220–225 MHz) and the UHF 70 centimeter (420–450 MHz) bands, but can be used on almost any frequency pair above 28 MHz . In some areas, 33 centimeters (902–928 MHz) and 23 centimeters (1.24–1.3 GHz) are also used for repeaters. Note that different countries have different rules; for example, in

9240-482: The high frequency bands with global coverage. Other modes, such as FSK441 using software such as WSJT , are used for weak signal modes including meteor scatter and moonbounce communications. Fast scan amateur television has gained popularity as hobbyists adapt inexpensive consumer video electronics like camcorders and video cards in PCs . Because of the wide bandwidth and stable signals required, amateur television

9380-426: The light bulb , and the computer , several inventors pioneered experimental work on voice transmission over a wire and improved on each other's ideas. New controversies over the issue still arise from time to time. Charles Bourseul , Antonio Meucci , Johann Philipp Reis , Alexander Graham Bell , and Elisha Gray , amongst others, have all been credited with the invention of the telephone. Alexander Graham Bell

9520-420: The model 500 telephone in the United States, were developed that permitted larger local networks centered around central offices. A breakthrough new technology was the introduction of Touch-Tone signaling using push-button telephones by American Telephone & Telegraph Company (AT&T) in 1963. The invention of the transistor in 1947 dramatically changed the technology used in telephone systems and in

9660-444: The radio spectrum , but within these bands are allowed to transmit on any frequency using a variety of voice, text, image, and data communications modes. This enables communication across a city, region, country, continent, the world, or even into space. In many countries, amateur radio operators may also send, receive, or relay radio communications between computers or transceivers connected to secure virtual private networks on

9800-447: The smartphone , the dominant type of telephone in the world today. Before the development of the electric telephone, the term telephone was applied to other inventions, and not all early researchers of the electrical device used the term. Perhaps the earliest use of the word for a communications system was the telephon created by Gottfried Huth in 1796. Huth proposed an alternative to the optical telegraph of Claude Chappe in which

9940-658: The 1990s, mobile phones have gained other features which are not directly related to their primary function as telephones. These include text messaging, calendars, alarm clocks, personal schedulers, cameras, music players, games and later, internet access and smartphone functionality. Nearly all mobile phones have the ability to send text messages to other users via the SMS (Short Message Service) protocol. The multimedia messaging service (MMS) protocol enables users to send and receive multimedia content, such as photos, audio files and video files. As their functionality has increased over

10080-495: The 432.000 MHz to 432.100 MHz frequencies and transmits on the 146.000 MHz to 146.100 MHz frequencies by inverting the frequency range within the band. In this example, a signal received at 432.001 MHz would be transmitted on 146.099 MHz. Voice signals using upper sideband modulation on the input would result in a LSB modulation on the output, and vice versa. "Phase 3D Satellite Primer" . Another class of repeaters do not simultaneously retransmit

10220-686: The Amateur Radio spectrum and more desirable (shorter) call signs. An exam, authorized by the Federal Communications Commission (FCC), is required for all levels of the Amateur Radio license. These exams are administered by Volunteer Examiners, accredited by the FCC-recognized Volunteer Examiner Coordinator (VEC) system. The Technician Class and General Class exams consist of 35 multiple-choice questions, drawn randomly from

10360-524: The CW mode—particularly on the shortwave bands and for experimental work, such as Earth–Moon–Earth communication , because of its inherent signal-to-noise ratio advantages. Morse, using internationally agreed message encodings such as the Q code , enables communication between amateurs who speak different languages. It is also popular with homebrewers and in particular with "QRP" or very-low-power enthusiasts, as CW-only transmitters are simpler to construct, and

10500-580: The Federal Communications Commission regulates the Amateur Radio Service. The United States Code of Federal Regulations Title 47 CFR, Part 97, which are the laws in which the Amateur Radio Service is regulated clearly states the definition of Frequency Coordinator. The purpose of coordinating a repeater or frequency is to reduce harmful interference to other fixed operations. Coordinating a repeater or frequency with other fixed operations demonstrates good engineering and amateur practice. In

10640-589: The ITU convention for the numeral. In the United Kingdom the original calls G0xxx, G2xxx, G3xxx, G4xxx, were Full (A) License holders along with the last M0xxx full call signs issued by the City & Guilds examination authority in December 2003. Additional Full Licenses were originally granted to (B) Licenses with G1xxx, G6xxx, G7xxx, G8xxx and 1991 onward with M1xxx call signs. The newer three-level Intermediate License holders are assigned 2E0xxx and 2E1xxx, and

10780-507: The ITU's Table of Frequency Allocations . These allocations may only apply to a group of countries. Amateur radio The amateur radio service ( amateur service and amateur-satellite service ) is established by the International Telecommunication Union (ITU) through the Radio Regulations . National governments regulate technical and operational characteristics of transmissions and issue individual station licenses with

10920-503: The Isle of Man, "GJ" & "MJ" are Jersey and "GU" & "MU" are Guernsey. Intermediate licence call signs are slightly different. They begin 2#0 and 2#1 where the # is replaced with the country letters as above. For example "2M0" and "2M1" are Scotland, "2W0" and "2W1" are Wales and so on. The exception however is for England. The letter "E" is used, but only in intermediate-level call signs. For example "2E0" & "2E1" are used whereas

11060-461: The Organization of American States to facilitate licensing reciprocity. When traveling abroad, visiting amateur operators must follow the rules of the country in which they wish to operate. Some countries have reciprocal international operating agreements allowing hams from other countries to operate within their borders with just their home country license. Other host countries require that

11200-533: The RF spectrum, usually allowing choice of an effective frequency for communications across a local, regional, or worldwide path. The shortwave bands, or HF , are suitable for worldwide communication, and the VHF and UHF bands normally provide local or regional communication, while the microwave bands have enough space, or bandwidth , for amateur television transmissions and high-speed computer networks . In most countries, an amateur radio license grants permission to

11340-428: The UK & Europe) may issue specialty vehicle registration plates to licensed amateur radio operators. The fees for application and renewal are usually less than the standard rate for specialty plates. In most administrations, unlike other RF spectrum users, radio amateurs may build or modify transmitting equipment for their own use within the amateur spectrum without the need to obtain government certification of

11480-510: The UK, the frequency allocations for repeaters are managed by the Emerging Technology Co-ordination Committee (ETCC) of the Radio Society of Great Britain and licensed by Ofcom , the industry regulator for communications in the UK. Each repeater has a NOV (Notice of Variation) licence issued to a particular amateur radio callsign (this person is normally known as the "repeater keeper") thus ensuring

11620-552: The United Kingdom and Australia, have begun requiring a practical assessment in addition to the written exams in order to obtain a beginner's license, which they call a Foundation License. In most countries, an operator will be assigned a call sign with their license. In some countries, a separate "station license" is required for any station used by an amateur radio operator. Amateur radio licenses may also be granted to organizations or clubs. In some countries, hams were allowed to operate only club stations. An amateur radio license

11760-562: The United States, the two-meter band is 144–148 MHz, while in the United Kingdom (and most of Europe) it is 144–146 MHz. Repeater frequency sets are known as "repeater pairs", and in the ham radio community most follow ad hoc standards for the difference between the two frequencies, commonly called the offset . In the USA two-meter band, the standard offset is 600 kHz (0.6 MHz), but sometimes unusual offsets, referred to as oddball splits , are used. The actual frequency pair used

11900-493: The advent of smartphones, mobile phone manufacturers have also included consumer electronics companies, such as Apple , Samsung and Xiaomi . As of 2022, most mobile phones are smartphones, being a combination of a mobile phone and a personal computing device in the same unit. Most smartphones are primarily operated using a graphical user interface and a touch screen. Many phones have a secondary voice user interface, such as Siri on Apple iPhones , which can operate many of

12040-763: The air. Some join in regularly scheduled on-air meetings with other amateur radio operators, called " nets " (as in "networks"), which are moderated by a station referred to as "Net Control". Nets can allow operators to learn procedures for emergencies, be an informal round table, or cover specific interests shared by a group. Amateur radio operators, using battery- or generator-powered equipment, often provide essential communications services when regular channels are unavailable due to natural disaster or other disruptive events . Many amateur radio operators participate in radio contests, during which an individual or team of operators typically seek to contact and exchange information with as many other amateur radio stations as possible in

12180-470: The amateur satellites, which are also known as OSCARs . Several satellites with amateur radio equipment on board have been designed and built by universities around the world. Also, several OSCARs have been built for experimentation. For example, NASA and AMSAT coordinated the release of SuitSat which was an attempt to make a low cost experimental satellite from a discarded Russian spacesuit outfitted with amateur radio equipment. The repeaters on board

12320-513: The basic Foundation License holders are granted call signs M3xxx, M6xxx or M7xxx. Instead of using numbers, in the UK the second letter after the initial 'G' or 'M' identifies the station's location; for example, a call sign G7OOE becomes GM7OOE and M0RDM becomes MM0RDM when that license holder is operating a station in Scotland. Prefix "GM" & "MM" are Scotland, "GW" & "MW" are Wales, "GI" & "MI" are Northern Ireland, "GD" & "MD" are

12460-426: The beginning of the 20th century did not place long-distance calls from their own telephones but made an appointment and were connected with the assistance of a telephone operator. What turned out to be the most popular and longest-lasting physical style of telephone was introduced in the early 20th century, including Bell's 202-type desk set. A carbon granule transmitter and electromagnetic receiver were united in

12600-513: The bell coil to allow the AC ringer signal through while still blocking DC (keeping the phone " on hook "). Telephones connected to the earliest Strowger switch automatic exchanges had seven wires, one for the knife switch , one for each telegraph key , one for the bell, one for the push-button and two for speaking. Large wall telephones in the early 20th century usually incorporated the bell, and separate bell boxes for desk phones dwindled away in

12740-431: The best quieting (strongest) signal, and the output of the selector will actually trigger the central repeater transmitter. A properly adjusted voting system can switch many times a second and can actually "assemble" a multi-syllable word using a different satellite receiver for each syllable. Such a system can be used to widen coverage to low power mobile radios or handheld radios that otherwise would not be able to key up

12880-446: The call signs beginning G or M for foundation and full licenses never use the "E". In the United States, for non-vanity licenses, the numeral indicates the geographical district the holder resided in when the license was first issued. Prior to 1978, US hams were required to obtain a new call sign if they moved out of their geographic district. In Canada, call signs start with VA, VE, VY, VO, and CY. Call signs starting with 'V' end with

13020-651: The central location, but can receive the signal from the central location without an issue. Voting systems require no knowledge or effort on the part of the user – the system just seems to have better-than-average handheld coverage. Repeaters may also be connected over the Internet using voice over IP ( VoIP ) techniques. VoIP links are a convenient way to connecting distant repeaters that would otherwise be unreachable by VHF/UHF radio propagation. Popular VoIP amateur radio network protocols include AllStarLink/HamVoIP, D-STAR , Echolink , IRLP , WIRES and eQSO . Digital Mobile Radio (DMR), D-STAR, Fusion, P25 and NXDN all have

13160-439: The circuit (as used in telegraphs ). The earliest dynamic telephones also had only one port opening for sound, with the user alternately listening and speaking (or rather, shouting) into the same hole. Sometimes the instruments were operated in pairs at each end, making conversation more convenient but also more expensive. At first, the benefits of a telephone exchange were not exploited. Instead, telephones were leased in pairs to

13300-501: The classroom to teach English, map skills, geography, math, science, and computer skills. The term "ham" was first a pejorative term used in professional wired telegraphy during the 19th century, to mock operators with poor Morse code -sending skills (" ham-fisted "). This term continued to be used after the invention of radio and the proliferation of amateur experimentation with wireless telegraphy; among land- and sea-based professional radio operators, "ham" amateurs were considered

13440-420: The device's functions, as well as enabling users to use spoken commands to interact with the internet. Typically alphanumeric text input is accomplished via an on-screen virtual keyboard, although some smartphones have a small physical keyboard. Smartphones offer the ability to access internet data through the cellular network and via wi-fi, and usually allow direct connectivity to other devices via Bluetooth or

13580-764: The early 20th century. The First Annual Official Wireless Blue Book of the Wireless Association of America , produced in 1909, contains a list of amateur radio stations. This radio callbook lists wireless telegraph stations in Canada and the United States, including 89 amateur radio stations. As with radio in general, amateur radio was associated with various amateur experimenters and hobbyists. Amateur radio enthusiasts have significantly contributed to science , engineering , industry, and social services . Research by amateur operators has founded new industries, built economies, empowered nations, and saved lives in times of emergency. Ham radio can also be used in

13720-408: The equipment. Licensed amateurs can also use any frequency in their bands (rather than being allocated fixed frequencies or channels) and can operate medium-to-high-powered equipment on a wide range of frequencies so long as they meet certain technical parameters including occupied bandwidth, power, and prevention of spurious emission . Radio amateurs have access to frequency allocations throughout

13860-524: The first digital cellular networks appearing in the early 1990s. Mobile phones require a SIM card to be inserted into the phone. The SIM card is a small PVC card containing a small integrated circuit which stores the user's international mobile subscriber identity (IMSI) number and its related key, which are used to identify and authenticate subscribers to the cellular network. Mobile phones generally incorporate an LCD or OLED display, with some types, such as smartphones, having touch screens. Since

14000-430: The handset was on the cradle. In the 1930s, telephone sets were developed that combined the bell and induction coil with the desk set, obviating a separate ringer box. The rotary dial becoming commonplace in the 1930s in many areas enabled customer-dialed service, but some magneto systems remained even into the 1960s. After World War II, the telephone networks saw rapid expansion and more efficient telephone sets, such as

14140-423: The help of a mentor, teacher, or friend. In North America, established amateurs who help newcomers are often referred to as "Elmers", as coined by Rodney Newkirk, W9BRD, within the ham community. In addition, many countries have national amateur radio societies which encourage newcomers and work with government communications regulation authorities for the benefit of all radio amateurs. The oldest of these societies

14280-822: The human ear-brain signal processing system can pull weak CW signals out of the noise where voice signals would be totally inaudible. A similar "legacy" mode popular with home constructors is amplitude modulation (AM), pursued by many vintage amateur radio enthusiasts and aficionados of vacuum tube technology. Demonstrating a proficiency in Morse code was for many years a requirement to obtain an amateur license to transmit on frequencies below 30 MHz. Following changes in international regulations in 2003, countries are no longer required to demand proficiency. The United States Federal Communications Commission , for example, phased out this requirement for all license classes on 23 February 2007. Modern personal computers have encouraged

14420-570: The key concepts of electronics, radio equipment, antennas, radio propagation , RF safety, and the radio regulations of the government granting the license. These examinations are sets of questions typically posed in either a short answer or multiple-choice format. Examinations can be administered by bureaucrats , non-paid certified examiners, or previously licensed amateur radio operators. The ease with which an individual can acquire an amateur radio license varies from country to country. In some countries, examinations may be offered only once or twice

14560-417: The license holder to own, modify, and operate equipment that is not certified by a governmental regulatory agency. This encourages amateur radio operators to experiment with home-constructed or modified equipment. The use of such equipment must still satisfy national and international standards on spurious emissions . Amateur radio operators are encouraged both by regulations and tradition of respectful use of

14700-437: The licensing authority has a single point of contact for that particular repeater. Each repeater in the UK is normally supported by a repeater group composed of local amateur radio enthusiasts who pay a nominal amount e.g. £10–15 a year each to support the maintenance of each repeater and to pay for site rents, electricity costs etc. Repeater groups do not receive any central funding from other organisations. Such groups include

14840-585: The licensing test, the ham writes three most-preferred options). Two-letter call sign suffixes require a ham to have already been licensed for 5 years. Call signs in Canada can be requested with a fee. Also, for smaller geopolitical entities, the numeral may be part of the country identification. For example, VP2xxx is in the British West Indies, which is subdivided into VP2Exx Anguilla, VP2Mxx Montserrat, and VP2Vxx British Virgin Islands. VP5xxx

14980-428: The long-distance transmission networks, over the next several decades. With the development of stored program control and MOS integrated circuits for electronic switching systems , and new transmission technologies such as pulse-code modulation (PCM), telephony gradually evolved towards digital telephony , which improved the capacity, quality, and cost of the network. Integrated Services Digital Network (ISDN)

15120-433: The mid-20th century for transmission between mobile stations on ships and in automobiles. Hand-held mobile phones were introduced for personal service starting in 1973. In later decades, the analog cellular system evolved into digital networks with greater capability and lower cost. Convergence in communication services has provided a broad spectrum of capabilities in cell phones, including mobile computing, giving rise to

15260-435: The middle of the century. Rural and other telephones that were not on a common battery exchange had a magneto hand-cranked generator to produce a high voltage alternating signal to ring the bells of other telephones on the line and to alert the operator. Some local farming communities that were not connected to the main networks set up barbed wire telephone lines that exploited the existing system of field fences to transmit

15400-495: The operators in the signaling towers would shout to each other by means of what he called "speaking tubes", but would now be called giant megaphones . A communication device for sailing vessels, called telephone , was invented by Captain John Taylor in 1844. This instrument used four air horns to communicate with vessels in foggy weather. Johann Philipp Reis used the term in reference to his invention, commonly known as

15540-436: The output frequency, "−" or "minus" for a lower frequency) with the assumption that the repeater uses the standard offset for the band in question. For instance, a 2-meter repeater might be described as "147.36 with a plus offset", meaning that the repeater transmits on 147.36 MHz and receives on 147.96 MHz, 600 kHz above the output frequency. Services provided by a repeater may include an autopatch connection to

15680-892: The privilege to operate in larger segments of the radio frequency spectrum, with a wider variety of communication techniques, and with higher power levels relative to unlicensed personal radio services (such as CB radio , FRS , and PMR446 ), which require type-approved equipment restricted in mode, range, and power. Amateur licensing is a routine civil administrative matter in many countries. Amateurs therein must pass an examination to demonstrate technical knowledge, operating competence, and awareness of legal and regulatory requirements, in order to avoid interfering with other amateurs and other radio services. A series of exams are often available, each progressively more challenging and granting more privileges: greater frequency availability, higher power output, permitted experimentation, and, in some countries, distinctive call signs. Some countries, such as

15820-501: The public safety agencies numbers programmed as speed-dial numbers. Repeater coordination is not required by the Federal Communications Commission, nor does the FCC regulate, certify or otherwise regulate frequency coordination for the Amateur Radio Bands. Amateur Radio Repeater Coordinators or coordination groups are all volunteers and have no legal authority to assume jurisdictional or regional control in any area where

15960-622: The receiver picks up for a set length of time (usually 30 seconds or less), then plays back the recording over the transmitter on the same frequency. A common name is a "parrot" repeater. Another form of repeater used in amateur packet radio , a form of digital computer-to-computer communications, is dubbed "digipeater" (for DIGItal rePEATER). Digipeaters are often used for activities and modes such as packet radio, Automatic Packet Reporting System , and D-STAR 's digital data mode. Also commercial digital modes such as DMR, P25 and NXDN. Some modes are full duplex and internet linked. An SSTV repeater

16100-409: The receiver was included in the local loop. The coupling transformer and the ringer were mounted in a separate enclosure, called the subscriber set. The dial switch in the base interrupted the line current by repeatedly but very briefly disconnecting the line one to ten times for each digit, and the hook switch (in the center of the circuit diagram) disconnected the line and the transmitter battery while

16240-428: The repeater would do the opposite, listening on 146.34 and transmitting on 146.94). In areas with many repeaters, "reverse splits" were common (i.e., 94/34), to prevent interference between systems. Since the late 1970s, the use of synthesized, microprocessor-controlled radios, and widespread adoption of standard frequency splits have changed the way repeater pairs are described. In 1980, a ham might have been told that

16380-693: The repeaters are made via radio (usually on a different frequency from the published transmitting frequency) for maximum reliability. Some networks have a feature to allow the user being able to turn additional repeaters and links on or off on the network. This feature is typically done with DTMF tones to control the network infrastructure. Such a system allows coverage over a wide area, enabling communication between amateurs often hundreds of miles (several hundred km) apart. These systems are used for area or regional communications, for example in Skywarn nets, where storm spotters relay severe weather reports. All

16520-430: The same time. This avoids the use of complex duplexers to achieve the required rejection for same band repeating. Most modern dual-band amateur transceivers are capable of cross-band repeat. Amateur television (ATV) repeaters are used by amateur radio operators to transmit full motion video. The bands used by ATV repeaters vary by country, but in the US a typical configuration is as a cross-band system with an input on

16660-403: The signal. In the 1890s a new smaller style of telephone was introduced, packaged in three parts. The transmitter stood on a stand, known as a " candlestick " for its shape. When not in use, the receiver hung on a hook with a switch in it, known as a "switchhook". Previous telephones required the user to operate a separate switch to connect either the voice or the bell. With the new kind, the user

16800-406: The signals into audible sound in the receiver or sometimes a loudspeaker . Telephones permit transmission in both directions simultaneously. Most telephones also contain an alerting feature, such as a ringer or a visual indicator, to announce an incoming telephone call. Telephone calls are initiated most commonly with a keypad or dial, affixed to the telephone, to enter a telephone number , which

16940-510: The size of their keyboards. Typically, smartphones feature such tools as cameras, media players, web browsers, email clients, interactive maps, satellite navigation and a variety of sensors, such as a compass , accelerometers and GPS receivers . In addition to voice calls, smartphone users commonly communicate using a wide variety of messaging formats, including SMS, MMS, email, and various proprietary messaging services, such as iMessage and various social media platforms. In 2002, only 10% of

17080-434: The software it uses (MMSSTV, JVComm32, MSCAN, for example), an SSTV repeater typically operates in common SSTV modes. Repeaters may be linked together in order to form what is known as a linked repeater system or linked repeater network . In such a system, when one repeater is keyed-up by receiving a signal, all the other repeaters in the network are also activated and will transmit the same signal. The connections between

17220-497: The spectrum to use as little power as possible to accomplish the communication. This is to minimise interference or EMC to any other device. Although allowable power levels are moderate by commercial standards, they are sufficient to enable global communication. Lower license classes usually have lower power limits; for example, the lowest license class in the UK (Foundation licence) has a limit of 10 W. Power limits vary from country to country and between license classes within

17360-453: The telephone switch, which allowed for the formation of telephone exchanges , and eventually networks. In the United Kingdom, the blower is used as a slang term for a telephone. The term came from navy slang for a speaking tube . In the U.S., a somewhat dated slang term refers to the telephone as "the horn," as in "I couldn't get him on the horn," or "I'll be off the horn in a moment." Early telephones were technically diverse. Some used

17500-408: The telephone to work a fluctuating current reproduced sounds the best. The fluctuating currents became the basis for the working telephone, creating Bell's patent. That first patent by Bell was the master patent of the telephone, from which other patents for electric telephone devices and features flowed. In 1876, shortly after Bell's patent application, Hungarian engineer Tivadar Puskás proposed

17640-543: The tower and one antenna. Most repeaters are remotely controlled through the use of audio tones on a control channel. A cross-band repeater (also sometimes called a replexer), is a repeater that retransmits a specific mode on a frequency in one band to a specific mode on a frequency in a different band. This technique allows for a smaller and less complex repeater system. Repeating signals across widely separated frequency bands allows for simple filters to be used to allow one antenna to be used for both transmit and receive at

17780-409: The transmission of another amateur station on a different channel or channels." (CFR 47 97.205(b)) Store-and-forward systems neither retransmit simultaneously, nor use a different channel. Thus, they must be operated under different rules than more conventional repeaters. A type of system known as a simplex repeater uses a single transceiver and a short-duration voice recorder, which records whatever

17920-437: The transmit and receive signals over a single antenna. The duplexer is a device which prevents the repeater's high-power transmitter (on the output frequency) from drowning out the users' signal on the repeater receiver (on the input frequency). A diplexer allows two transmitters on different frequencies to use one antenna, and is common in installations where one repeater on 2 m and a second on 440 MHz share one feedline up

18060-442: The use of digital modes such as radioteletype (RTTY) which previously required cumbersome mechanical equipment. Hams led the development of packet radio in the 1970s, which has employed protocols such as AX.25 and TCP/IP . Specialized digital modes such as PSK31 allow real-time, low-power communications on the shortwave bands but have been losing favor in place of newer digital modes such as FT8 . Radio over IP , or RoIP,

18200-465: The user has to know is which channel to use in which area. In order to get better receive coverage over a wide area, a similar linked setup can also be done with what is known as a voted receiver system . In a voted receiver, there are several satellite receivers set up to receive on the same frequency (the one that the users transmit on). All of the satellite receivers are linked to a voting selector panel that switches from receiver to receiver based on

18340-461: The visiting ham apply for a formal permit, or even a new host country-issued license, in advance. The reciprocal recognition of licenses frequently not only depends on the involved licensing authorities, but also on the nationality of the bearer. As an example, in the US, foreign licenses are recognized only if the bearer does not have US citizenship and holds no US license (which may differ in terms of operating privileges and restrictions). Conversely,

18480-645: The world are regularly involved with amateur radio. About 830,000 amateur radio stations are located in IARU Region 2 (the Americas) followed by IARU Region 3 (South and East Asia and the Pacific Ocean) with about 750,000 stations. A significantly smaller number, about 400,000, are located in IARU Region 1 (Europe, Middle East, CIS , Africa). The origins of amateur radio can be traced to the late 19th century, but amateur radio as practised today began in

18620-456: The world's population used mobile phones and by 2005 that percentage had risen to 46%. By the end of 2009, there were a total of nearly 6 billion mobile and fixed-line telephone subscribers worldwide. This included 1.26 billion fixed-line subscribers and 4.6 billion mobile subscribers. A satellite telephone, or satphone, is a type of mobile phone that connects to other phones or the telephone network by radio link through satellites orbiting

18760-517: The years, many types of mobile phone, notably smartphones, require an operating system to run. Popular mobile phone operating systems in the past have included Symbian , Palm OS , BlackBerry OS and mobile phone versions of Windows . As of 2022, the most used operating systems are Google's Android and Apple's iOS . Before the era of smartphones, mobile phones were generally manufactured by companies specializing in telecommunications equipment, such as Nokia , Motorola , and Ericsson . Since

18900-425: Was $ 85.2 billion with a projection of $ 102.5 billion by 2026. IP telephony uses high-bandwidth Internet connections and specialized customer premises equipment to transmit telephone calls via the Internet, or any modern private data network. The customer equipment may be an analog telephone adapter (ATA) which translates the signals of a conventional analog telephone; an IP Phone , a dedicated standalone device; or

19040-570: Was crucial. Most, however, used the Edison/Berliner carbon transmitter , which was much louder than the other kinds, even though it required an induction coil which was an impedance matching transformer to make it compatible with the impedance of the line. The Edison patents kept the Bell monopoly viable into the 20th century, by which time the network was more important than the instrument. Early telephones were locally powered, using either

19180-466: Was launched in the 1980's, providing businesses and consumers with access to digital telephony services such as data, voice, video , and fax services. The development of digital data communications methods made it possible to digitize voice and transmit it as real-time data across computer networks and the Internet , giving rise to the field of Internet Protocol (IP) telephony, also known as voice over Internet Protocol (VoIP). VoIP has proven to be

19320-406: Was less likely to leave the phone "off the hook". In phones connected to magneto exchanges, the bell, induction coil, battery and magneto were in a separate bell box or " ringer box ". In phones connected to common battery exchanges, the ringer box was installed under a desk, or other out-of-the-way place, since it did not need a battery or magneto. Cradle designs were also used at this time, having

19460-407: Was not slow in appreciating the potential. Signalling began in an appropriately primitive manner. The user alerted the other end, or the exchange operator , by whistling into the transmitter. Exchange operation soon resulted in telephones being equipped with a bell in a ringer box , first operated over a second wire, and later over the same wire, but with a condenser ( capacitor ) in series with

19600-550: Was the first to be awarded a patent for the electric telephone by the United States Patent and Trademark Office (USPTO) in March 1876. Before Bell's patent, the telephone transmitted sound in a way that was similar to the telegraph. This method used vibrations and circuits to send electrical pulses, but was missing key features. Bell found that this method produced a sound through intermittent currents, but in order for

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