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61-486: CT1 stands for Cordless telephone generation 1 and is an analog cordless telephone standard that was standardized by the European Conference of Postal and Telecommunications Administrations (CEPT) in 1984 and deployed in eleven European countries. The initial set of frequencies provided for a set 40 duplex channels using 25 kHz separation, with the phones transmitting in the 914-915 MHz band and

122-403: A wireless access point or base station that supports the same technology. Also required is a call management function and a gateway to the public switched telephone network (PSTN). This may or may not be integrated in the base-station. A Voice over IP service can be used by phones that use wireless data access points, thus using a broadband Internet connection to defer the connection to

183-618: A Malaitan enclave and the Malaita Eagle Force took over government. The Royal Australian Navy and Royal New Zealand Navy deployed vessels to the area to protect the expatriate community resident mostly in Honiara. In 2003, the Pacific Forum negotiated the intervention of RAMSI or Operation Helpem Fren involving Australia, New Zealand, and other Pacific island nations. About 25 km (15 mi) from Honiara to

244-641: A basic form of scrambling to help limit unauthorized eavesdropping . These phones share the 49.8 MHz band (49.830 - 49.890) with some wireless baby monitors . 900 MHz cordless phones are rarely sold but have a huge installed base. Features include even shorter antennas, up to 30 auto selecting channels, and higher resistance to interference. Available in several varieties; analog, analog spread spectrum (100 kHz bandwidth), digital, and digital spread spectrum, most being sold today are low-cost analog models, which are still susceptible to eavesdropping. Digital variants can still be scanned, but are received as

305-515: A beach at Point Cruz; he was killed during the evacuation. During the Battle for Henderson Field , the Medal of Honor was also awarded to John Basilone , who was later killed in action during the Battle of Iwo Jima in 1945. After the war, American and Japanese groups repeatedly visited Guadalcanal to search for the remains of missing soldiers. The bodies of some 7,000 Japanese troops remain missing on

366-461: A couple of city blocks. These models became obsolete because they are susceptible to eavesdropping, and interference from fluorescent lighting and automobile ignition systems. However, under ideal conditions they could have 0.5 miles (0.80 km) or more range. 43–50 MHz cordless phones had a large installed base by the early 1990s, and featured shorter flexible antennas and automatic channel selection. Due to their popularity, an overcrowding of

427-528: A defensive ring around their conquests and threaten the lines of communication from the United States to Australia and New Zealand. The Japanese reached Guadalcanal in May 1942. When an American reconnaissance mission spotted construction of a Japanese airfield at Lunga Point on the north coast of Guadalcanal, the situation became critical. This new Japanese airfield represented a threat to Australia, so as

488-444: A digital hiss and therefore are difficult to eavesdrop upon. Digital transmission is immune to static interference but can experience signal fade (brief silence) as the phone goes out of range of the base. Newer Digital Spread Spectrum (DSS) variants spread their signal over a range of frequencies, providing more resistance to signal fade. This technology enabled the digital information to spread in pieces among several frequencies between

549-523: A duplex voice communication link including controls provided between a base station connected directly to a telephone line of a telephone exchange and a mobile unit consisting of a small, compact cordless telephone instrument containing transmitter, receiver and control circuits powered by a rechargeable battery pack. A single logic tone is transmitted and detected for all logical control for ring signals, on-hook and off-hook signals and dial pulses. Cordless phones became widely used in home and workplaces during

610-401: A host of other devices, including baby monitor , microwave oven , Bluetooth , and wireless LAN ; thus, it is likely that a cordless phone will suffer interference from signals broadcast by those devices, and also may itself generate interference. It is also possible for a cordless phone to interfere with the 802.11a wireless standard, as the 802.11a standard can be configured to operate in

671-579: A limited scale, international roaming . In specialized models, a commercial mobile network operator may maintain base stations and users subscribe to the service. Unlike a corded telephone, a cordless telephone needs mains electricity (to power the base station). The cordless handset contains a rechargeable battery , which the base station re-charges when the handset rests in its cradle. Radio telephony (telephony without wires) predated cordless phones by at least two decades. The first, MTS, or Mobile Telephone Service went into service in 1946. Because

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732-428: A matter of urgency, despite not being adequately prepared, the United States conducted its first amphibious landing of the war on Guadalcanal. The initial landings of the 1st Marine Division on 7 August 1942 secured the airfield with little difficulty, but holding the airfield for the next six months against combined Japanese ground assault, air attack and naval bombardment was one of the most hotly contested campaigns in

793-427: A particularly nasty bite. The Guadalcanal Watersheds form a site that has been identified by BirdLife International as an important bird area , because it supports populations of threatened or endemic bird species. At 376,146 ha (1,452 sq mi), it covers some 70% of the island, extending along the southern coast inland to the central highlands, and contains riverine and lowland tropical rainforest , as well as

854-503: A protectorate over the northern Solomons in 1884, while in 1893, the British Solomon Islands Protectorate was proclaimed, which included the island of Guadalcanal. Germany eventually handed over most of their protectorate to Britain, though, in 1899. By the early 20th century, large agricultural plantations (specialising in copra ), run mainly by Australians, were established in the region. Guadalcanal

915-501: A quality that is just adequate for the parties to understand each other. Typical bandwidth is 3.6 kHz; only a fraction of the frequencies that humans can hear, but enough to make the voice intelligible. No phone handset can improve on this quality, as it is a limitation of the phone system itself. Higher-quality phones can transfer this signal to the handset with less interference over a greater range, however. Most cordless telephones, no matter what frequency band or transmission method

976-436: Is illegal in many countries). Though many such analog models are still produced, modern digital technology is available to reduce the risk of eavesdropping . Digital Spread Spectrum (DSS) typically uses frequency hopping to spread the audio signal (with a 3 kHz bandwidth) over a much wider range of frequencies in a pseudorandom way. Spreading the signal out over a wider bandwidth is a form of redundancy , and increases

1037-399: Is no specific requirement for any particular transmission mode on the older bands, but in practice many legacy phones also have digital features such as DSSS and FHSS . Some cordless phones formerly advertised as 5.8 GHz actually transmit from base to phone on 5.8 GHz and transmit from phone to base on 2.4 GHz or 900 MHz, to conserve battery life. The 1.9 GHz band

1098-659: Is returned to the cradle. Additionally, the digital nature of the signal increases its tolerance to noise, and some systems even encrypt the digital signal for additional security. Roaming cordless phone handsets exist which are not tethered to any particular base station, but which also do not use traditional mobile (cellular) phone networks. These most commonly use digital technologies like DECT , 2.4 GHz unlicensed spectrum, or 802.11a /b/g standards-based wireless LAN technology. Analog equivalents do exist and can provide longer reach, but with potential loss of confidentiality and voice quality. The cordless phone handset connects to

1159-653: Is the principal island in Guadalcanal Province of Solomon Islands , located in the southwestern Pacific Ocean , northeast of Australia . It is the largest island in the Solomons by area and the second-largest by population (after Malaita ). The island is mainly covered in dense tropical rainforest and has a mountainous hinterland . Guadalcanal was first charted by Westerners during the Spanish expedition of Álvaro de Mendaña in 1568. The name comes from

1220-609: Is used by the DECT 6.0 phone standard and is considered more secure than the other shared frequencies. The vast majority of new cordless phone devices sold in North America, whether connected by landline or to mobile phones (usually via Bluetooth ), now use DECT 6.0. However, DECT 6.0's late start compared to DECT elsewhere has led to a large installed base of legacy cordless phones using other frequencies, many of which remain in use today despite increasingly common interference with

1281-502: Is used, will hardly ever exactly match the sound quality of a high-quality wired telephone attached to a good telephone line . This limitation is caused by a number of issues, including the following: Most manufacturers claim a range of about 30 metres (98 ft) for their 2.4 GHz and 5.8 GHz systems, but inexpensive models often fall short of this claim. However, the higher frequency often brings advantages. The 900 MHz and 2.4 GHz band are increasingly being used for

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1342-475: The Cactus Air Force . They defended the airfield and threatened any Japanese ships that ventured too close to the island during daylight hours. At night, however, Japanese naval forces were frequently able to shell the airfield and deliver troops with supplies, retiring before daylight. The Japanese used fast ships, namely destroyers, to conduct this reinforcement and supply effort, which became known as

1403-618: The Federal Communications Commission for uses that include cordless phones. These are: Over-crowding of earlier frequency allocations led users to discontinue using telephone equipment that operated on those frequencies, leaving those bands relatively clear. Radio hobbyists monitor usage of the older equipment with telephone activity in the US AM broadcast band, some 27 MHz frequencies and most older 43-50 MHz frequencies. 1.7 MHz cordless phones were

1464-518: The PSTN to a remote gateway operated by the service provider. Unlike wired telephones that are powered from the telephone company's central station batteries, a cordless phone base station required electrical power to operate. During a power interruption, the cordless base station will not be operable, while wired sets may continue to operate. Guadalcanal Guadalcanal ( / ˌ ɡ w ɑː d əl k ə ˈ n æ l / ; indigenous name: Isatabu )

1525-638: The Tokyo Express . So many ships from both sides were sunk in the many naval engagements in and around the Solomon Island chain that the nearby waters came to be referred to as Ironbottom Sound . The naval Battle of Cape Esperance was fought on 11 October 1942 in the waters off the northwest coast of Guadalcanal. During the engagement, the United States Navy intercepted and defeated a Japanese formation of ships on their way down "

1586-409: The signal-to-noise ratio , yielding longer range and less susceptibility to interference. Higher frequency bands provide more room for these wide-bandwidth signals. To an analog receiver like a scanner, a DSS signal sounds like bursts of noise. Only the base unit using a matching pseudorandom number can decode the signal, and it chooses from one of thousands of such unique codes each time the handset

1647-597: The 18th and 19th centuries. With these outsiders also arrived foreign institutions such as forced labour. Beginning during the 1860s, about 60,000 natives from many parts of the Solomon Islands were indentured and sent to Australia or Fiji by British authorities to work on plantations. This system continued into the 1890s. In the 1880s, the Germans and the British vied for control of the Solomons. Germany established

1708-566: The 21st century are digital. Digital technology has helped provide clear sound and limit casual eavesdropping. Many cordless phones have one main base station and can add up to three or four additional bases. This allows for multiple voice channels that allow three-way conference calls between the bases. This technology also allows multiple handsets to be used at the same time, and up to two handsets can have separate conversations with outside parties. Manufacturers usually advertise that their higher frequency systems improve audio quality and range. In

1769-495: The 5.8 GHz range. However, this can easily be fixed by reconfiguring the wireless LAN device to work in the 5.180 GHz to 5.320 GHz band. The newer 1.9 GHz band is reserved for use by phones that use the DECT standard, which should avoid interference issues in the unlicensed 900 MHz, 2.4 GHz, and 5.8 GHz bands. Many analog phone signals are easily picked up by radio scanners , allowing anyone within range to listen in on conversations (though this

1830-657: The Battle of Midway in turning the tide against them. After six months of hard combat in and around Guadalcanal, the Japanese forces on the island were critically undersupplied and no longer combat effective, while Allied troops were steadily increasing in quantity and quality. Remaining Japanese forces on the island were evacuated at Cape Esperance on the northwest coast in February 1943. American authorities declared Guadalcanal secure on 9 February 1943. The Guadalcanal campaign

1891-532: The Pacific theater of war that two battleships engaged each other in combat, with the next such engagement occurring in 1944 during the Battle of Leyte Gulf . Some Japanese viewpoints consider these naval engagements, which showcased the improving capability of Allied warships to challenge the Imperial Japanese Navy's significant advantage in night-fighting techniques, to be just as significant as

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1952-513: The Slot " to reinforce and resupply troops on the island, suffering losses of their own in the process. The multi-day Naval Battle of Guadalcanal in early November marked a critical turning point in the campaign. Allied naval forces engaged a large, experienced Japanese surface force at night and forced it to withdraw, sinking the IJN battleship Kirishima in the process. This was one of only two times in

2013-408: The band led to an allocation of additional frequencies; thus manufacturers were able to sell models with 25 channels instead of just 10 channels. Although less susceptible to interference than previous AM units, these models are no longer in production and are considered obsolete because their frequencies are easily heard on practically any radio scanner. Advanced models began to use voice inversion as

2074-438: The base stations in the 959-960 MHz band. These frequencies overlap with those used by channels 120-124 on GSM cellular phones and thus these original frequencies have been withdrawn from use for cordless phones in the countries that originally authorized them. CT1+ provided in 1987 for a set of 80 additional channels using the same technical standard with 885–887 MHz used by the phones and 930–932 MHz used by

2135-438: The base stations. While not part of the original GSM-900 band, the frequencies do overlap with the extended GSM-900 band. Thus between the advent of digital cordless telephones and the desire to free up spectrum for mobile telephones, these frequencies are being withdrawn for use as well. CT0 is a term used for pre-CT1 analog cordless telephones that were deployed in a variety of countries with incompatible standards, mostly in

2196-520: The direction of W.D. Goodale, Jr. By 1964, breadboard models were working in the lab. During 1964-65 these were refined and packaged to test around the Bell Labs Holmdel N.J. facilities. The system operated under an experimental license on crystal controlled channels in the 35 and 43 MHz bands using FM, a low power transmitter and a sensitive superhet receiver. Full supervision of all telephone functions, including on-off hook and dialing

2257-484: The earliest models available at retailers, and are generally identifiable by their large metal telescoping antennas. Channels just above the AM broadcast band were selected manually by the user. Some of the frequencies used are now part of the expanded AM radio band, and can be heard by anyone with an AM radio. There are reports of people still using these phones, and using them as makeshift AM radio stations that can be heard for

2318-622: The early 1980s. According to The New York Times , the number of cordless phones sold in the United States grew from 50,000 in 1980 to 1 million in 1982. They quickly became popular because of their convenience and portability, despite fears that their reliance on radio signals would make them vulnerable to eavesdropping or other malfeasance. In 1994, digital cordless phones in the 900 MHz frequency range became available to consumers. These new types of phones provided better audio quality because it could filter out interference and its signals could penetrate walls more easily. Digital signals allowed

2379-402: The entire Pacific theater of war. Immediately after landing on the island, U.S. Navy Seabees began finishing the airfield begun by the Japanese. It was then named Henderson Field after a Marine aviator killed in combat during the Battle of Midway . Aircraft operating from Henderson Field during the campaign were a mix of U.S. Marine, Army, Navy, and other Allied aircraft that became known as

2440-426: The ever growing use of Wi-Fi , Bluetooth and other unlicensed digital radio standards, especially at 2.4 GHz and 5.8 GHz. In Europe, the 1.9 GHz (1880–1900 MHz) band was set aside for the DECT phone standard from its inception. DECT, on its European band & related frequencies, has largely displaced all other cordless phone standards worldwide except for North America. Many cordless phones in

2501-448: The greatest contiguous area of cloud forest in the Solomons. Although it also contains gardens and old village sites, most of it has never been permanently inhabited. Significant birds for which the site was identified include chestnut-bellied imperial pigeons , Woodford's rails , Guadalcanal moustached kingfishers , Meek's lorikeets , Guadalcanal honeyeaters , Guadalcanal thicketbirds , and Guadalcanal thrushes . Potential threats to

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2562-476: The highest in Solomon Islands, with an elevation of 7,661 ft (2,335 m) above sea level. The Mbokokimbo River is the island's longest river, with a total length of 98.7 km (61.3 mi). List of peaks in Guadalcanal by elevation List of longest rivers by length The island has been settled since at least 4500–2500 BC based on archaeological finds at Poha Cave and Vatuluma Posovi. During

2623-437: The ideal case, higher frequencies actually have worse signal propagation as shown by the basic Friis transmission equation , and path loss tends to increase at higher frequencies as well. Practical influences on quality and range are signal strength , antenna quality, the method of modulation used, and interference, which varies locally. " Plain old telephone service " (POTS) landlines are designed to transfer audio with

2684-492: The island's shores. In recent times, these crocodiles have been found only on the Weather Coast in the south of the island, but during World War II, they were found along the north coast in the vicinity of the airstrip where the fighting was taking place, as evidenced by names such as Alligator Creek . Venomous snakes are rare on the island and are not considered to be a serious threat, but a kind of centipede there has

2745-699: The island, and islanders still bring the Japanese groups bones that they say are those of unearthed Japanese soldiers. Immediately after the Second World War, the capital of the British Solomon Islands Protectorate was moved to Honiara on Guadalcanal from its previous location at Tulagi in the Florida Islands . In 1952, the high commissioner for the Western Pacific moved from Fiji to Honiara, and

2806-447: The local Guale people on Guadalcanal and more recent migrants from the neighbouring island of Malaita erupted into violence. The Guadalcanal Revolutionary Army, later called Isatabu Freedom Movement , began terrorising Malaitans in the rural areas of the island in an effort to force them out of their homes. About 20,000 Malaitans fled to the capital, and others returned to their home island; Guale residents of Honiara fled. The city became

2867-621: The low VHF frequency range below broadcast Band I . Since 31 December 2008, CTA1 and CTA2 based phones are forbidden in Germany . Cordless telephone A cordless telephone differs functionally from a mobile telephone in its limited range and by depending on the base station on the subscriber premises. Current cordless telephone standards, such as PHS and DECT , have blurred the once clear-cut line between cordless and mobile telephones by implementing cell handoff (handover); various advanced features, such as data-transfer; and even, on

2928-483: The new capital of the British Solomon Islands Protectorate and later the capital of the independent nation of Solomon Islands. Guadalcanal is the largest island in Solomon Islands , with a total land area of 5,302 km (2,047 sq mi), and has a population of 155,605 people, making it the second-most populous island in the country after Malaita. Mount Popomanaseu is the island's highest point and

2989-737: The period 1200-800 BC, Austronesian Lapita peoples settled the islands. A Spanish expedition from Peru in 1568 under the command of Álvaro de Mendaña de Neira were the first Europeans to see the island. Mendaña's subordinate, Pedro de Ortega Valencia, named the island after his home town Guadalcanal in Andalusia, Spain. In the years that followed the discovery, the island was variously referred to as Guadarcana, Guarcana, Guadalcana, and Guadalcanar, which reflected different pronunciations of its name in Andalusian Spanish. European settlers, whalers, and missionaries began to arrive in

3050-456: The phones to be more secure and decreased eavesdropping; it was relatively easy to eavesdrop on analog cordless phone conversations. In 1995 digital spread spectrum (DSS) was introduced for cordless phones. This technology enabled the spreading of the digital voice transmission over multiple frequencies, improving privacy and reducing interference between different subscribers. In the United States, seven frequency bands have been allocated by

3111-414: The post was combined with that of the governor of the Solomon Islands. The airfield which was the cause of the fighting in 1942, and which became well known as Henderson Field, is now the international airport for the Solomon Islands. It sits about five miles to the east of Honiara. The secondary airfield, known as "Fighter Two", is now the local golf course. In early 1999, long-simmering tensions between

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3172-559: The range was intended to cover the widest possible service area, capacity was extremely low, and the early tube technology made equipment rather large and heavy. The second generation radio telephone, or IMTS, or Improved Mobile Telephone Service became active in 1964. Beginning in 1963, a small team of Bell Laboratories engineers were tasked with developing a practical and fully functional duplex wireless telephone. The team included (in alphabetic order): S.M. Baer, G.C. Balzer, J.M. Brown, W.F. Clemency, M. Rosenthal, and W. Zinsmeister, under

3233-500: The receiver and the base, thereby making it almost impossible to eavesdrop on the cordless conversation. The FCC only allows DSS model phones to transmit at the full power of 1 watt, which allows increased range over older analog and digital models. Virtually all new cordless phones sold in the US use DECT 6.0 on the 1.9 GHz band, though legacy phones can remain in use on the older 900 MHz, 2.4 GHz and 5.8 GHz bands. There

3294-573: The telephone, led to the reversal of the Federal Communications Commission ban on direct coupling of consumer equipment to phone lines (known as the landmark Carterfone decision) on June 26, 1968. The original cordless phones, like the Carterfone, were acoustically (not electrically) connected to the public telephone network. In 1977, Douglas G. Talley and L Duane Gregory were granted U.S. patent 4,039,760 for

3355-525: The village of Guadalcanal , in the province of Seville , in Andalusia , Spain, birthplace of Pedro de Ortega Valencia, a member of Mendaña's expedition. During 1942 and 1943, it was the scene of the Guadalcanal campaign and saw bitter fighting between Japanese and U.S. troops. The Americans were ultimately victorious. At the end of World War II , Honiara , on the north coast of Guadalcanal, became

3416-550: The west, Vilu War Museum houses an outdoor collection of remains of various parts of military equipment and of several aircraft. Several memorials for the American, Australian, Fijian, New Zealand, and Japanese soldiers who died were erected, as well. The island hosts a native marsupial known as the phalanger or grey cuscus, Phalanger orientalis . The only other mammals are bats and rodents. Many species of colourful parrots are found there, and estuarine crocodiles inhabit

3477-475: Was a major turning point in the war, as it stopped further Japanese expansion. Two U.S. Navy ships have been named for the campaign: To date, the only U.S. Coast Guardsman recipient of the Medal of Honor is Signalman 1st Class Douglas Albert Munro , awarded posthumously for his extraordinary heroism on 27 September 1942 at Point Cruz . Munro provided covering fire and helped evacuate 500 besieged Marines from

3538-453: Was an active proponent for directly coupling consumer electronics to the AT&;T -owned telephone lines in the late 1960s. The telephone companies at the time did not permit third-party equipment to be connected to their lines; most telephones were made by Western Electric and leased to the customer by AT&T. The Carterfone coupler, a crude device for interconnecting a two-way radio with

3599-752: Was described in the Bell Laboratories Record, Volume 45 (1967). In 1966, George Sweigert submitted a patent application for a " full duplex wireless communications apparatus". He was awarded U.S. patent 3,449,750 in June 1969. Sweigert, a radio operator in World War II stationed at the South Pacific Islands of Guadalcanal and Bougainville , developed the full duplex concept for untrained personnel, to improve battlefield communications for senior commanders. Sweigert

3660-736: Was not seriously affected by World War I. In 1932, the British confirmed the name Guadalcanal in line with the town in Andalusia, Spain. In the months following the attack on Pearl Harbor in December 1941, the Japanese drove the Americans out of the Philippines , the British out of British Malaya , and the Dutch out of the East Indies . The Japanese then began to expand into the western Pacific, occupying many islands in an attempt to build

3721-527: Was provided via an out of band tone supervision system. The model developed for home use was designed to look like a standard (although bulky) telephone handset. The base station was a small box connected to a standard telephone network. About 50 units were built in a Western Electric model shop in Andover Mass. for field trials in two Bell System locations in the Boston and Phoenix area. The overall project

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