Telecom Valley was an area located in Sonoma County, California specifically the Redwood Business Park of Petaluma, California .
158-821: Telecom Valley is the term coined for the North San Francisco Bay Area Highway 101 corridor between Petaluma and Santa Rosa in Northern California. It was derived from its South Bay Area cousin Silicon Valley . In 1969, Don Green, later nicknamed the "Father of Telecom Valley", founded Digital Telephone Systems (DTS) in San Rafael, CA. It is considered the original seed for Telecom Valley which developed farther north in Sonoma County driven by lower cost facilities and housing. Digital Telephone Systems
316-540: A CCITT standard. Similar schemes were used in the Americas and in some European countries including Spain. Digit strings between switches were often abbreviated to further improve utilization. For example, one switch might send only the last four or five digits of a telephone number . In one case, seven digit numbers were preceded by a digit 1 or 2 to differentiate between two area codes or office codes, (a two-digit-per-call savings). This improved revenue per trunk and reduced
474-747: A World Series game between two Bay Area baseball teams, the Loma Prieta earthquake struck and caused widespread infrastructural damage, including the failure of the Bay Bridge , a major link between San Francisco and Oakland . Even so, the Bay Area's technology industry continued to expand and growth in Silicon Valley accelerated: the United States census confirmed that year that San Jose had overtaken San Francisco in terms of population. The commercialization of
632-446: A panel switch and a manual switchboard. Probably the most common form of communicating dialed digits between electromechanical switches was sending dial pulses , equivalent to a rotary dial 's pulsing, but sent over trunk circuits between switches. In Bell System trunks, it was common to use 20 pulse-per-second between crossbar switches and crossbar tandems. This was twice the rate of Western Electric/Bell System telephone dials. Using
790-456: A central office (C.O.) is a common carrier switching center Class 5 telephone switch in which trunks and local loops are terminated and switched. In the UK, a telephone exchange means an exchange building, and is also the name for a telephone switch. With manual service , the customer lifts the receiver off-hook and asks the operator to connect the call to a requested number. Provided that
948-484: A circuit connecting a dialed call through an electromechanical switch had DC continuity within the local exchange area via metallic conductors. The design and maintenance procedures of all systems involved methods to avoid that subscribers experienced undue changes in the quality of the service or that they noticed failures. A variety of tools referred to as make-busy s were plugged into electromechanical switch elements upon failure and during repairs. A make-busy identified
1106-449: A complex multimodal transportation network. The earliest archaeological evidence of human settlements in the Bay Area dates back to 8000–10,000 BC. The oral tradition of the Ohlone and Miwok people suggests they have been living in the Bay Area for several hundreds if not thousands of years. The Spanish empire claimed the area beginning in the early period of Spanish colonization of
1264-412: A digit receiver (part of an element called an Originating Register ) would be connected to a call just long enough to collect the subscriber's dialed digits. Crossbar architecture was more flexible than step offices. Later crossbar systems had punch-card-based trouble reporting systems. By the 1970s, automatic number identification had been retrofitted to nearly all step-by-step and crossbar switches in
1422-517: A failed switch element. A trouble reporting card system was connected to switch common control elements. These trouble reporting systems punctured cardboard cards with a code that logged the nature of a failure. Electromechanical switching systems required sources of electricity in form of direct current (DC), as well as alternating ring current (AC), which were generated on-site with mechanical generators. In addition, telephone switches required adjustment of many mechanical parts. Unlike modern switches,
1580-620: A few years earlier, which now provides drinking water for 2.4 million people in the Bay Area. By 1915, the city had been sufficiently rebuilt and advertised itself to the world during the Panama Pacific Exposition that year, although the effects of the quake hastened the loss of the region's dominant status in California to the Los Angeles metropolitan area . During the 1929 stock market crash and subsequent economic depression , not
1738-552: A first in the United States, and four years later a majority of voters in the Bay Area rejected California Proposition 8 , which sought to constitutionally restrict marriage to opposite-sex couples but ultimately passed statewide. The Bay Area was also the center of contentious protests concerning racial and economic inequality . In 2009, an African-American man named Oscar Grant was fatally shot by Bay Area Rapid Transit police officers , precipitating widespread protests across
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#17330853427261896-404: A horizontal panel containing two rows of patch cords, each pair connected to a cord circuit . When a calling party lifted the receiver, the local loop current lit a signal lamp near the jack. The operator responded by inserting the rear cord ( answering cord ) into the subscriber's jack and switched their headset into the circuit to ask, "Number, please?" For a local call, the operator inserted
2054-411: A hundred pair cable between switches, for example. Conductors in one common circuit configuration were named tip, ring, ear (E) and mouth (M). Tip and ring were the voice-carrying pair, and named after the tip and ring on the three conductor cords on the manual operator's console. In two-way trunks with E and M signaling , a handshake took place to prevent both switches from colliding by dialing calls on
2212-485: A lamp on the operator's switchboard, signaling the operator to perform service. In the largest cities, it took many years to convert every office to automatic equipment, such as a panel switch . During this transition period, once numbers were standardized to the 2L-4N or 2L-5N format (two-letter exchange name and either four or five digits), it was possible to dial a number located in a manual exchange and be connected without requesting operator assistance. The policy of
2370-722: A major domestic military and naval hub, with large shipyards constructed in Sausalito and across the East Bay to build ships for the war effort. The Army's San Francisco Port of Embarkation was the primary origin for Army forces shipping out to the Pacific Theater of Operations . That command consisted of fourteen installations including Fort Mason, the Oakland Army Base , Camp Stoneman and Fort McDowell in San Francisco Bay and
2528-399: A manual office, having listings such as Hillside 834 or East 23, was recognizable by the format in which the second letter was not capitalized. Rural areas, as well as the smallest towns, had manual service and signaling was accomplished with magneto telephones, which had a crank for the signaling generator. To alert the operator, or another subscriber on the same line, the subscriber turned
2686-407: A private telephone exchange is termed a private branch exchange (PBX), which connects to the public switched telephone network. A PBX serves an organization's telephones and any private leased line circuits, typically situated in large office spaces or organizational campuses. Smaller setups might use a PBX or key telephone system managed by a receptionist, catering to the telecommunication needs of
2844-467: A rate of one thousand per week on their way to California's interior, including the first large influx of Chinese immigrants to the U.S. The rush was so great that vessels were abandoned by the hundreds in San Francisco's ports as crews rushed to the goldfields. The unprecedented influx of new arrivals spread the nascent government authorities thin, and the military was unable to prevent desertions. As
3002-461: A result, numerous vigilante groups formed to provide order, but many tasked themselves with forcibly moving or killing local Native Americans , and by the end of the Gold Rush, two thirds of the indigenous population had been killed. During this same time, a constitutional convention was called to determine California's application for statehood into the United States. After statehood was granted,
3160-494: A significant earthquake hazard. Among the more well-understood faults, as of 2014, scientists estimate a 72% probability of a magnitude 6.7 earthquake occurring along either the Hayward, Rogers Creek, or San Andreas fault, with an earthquake more likely to occur in the East Bay's Hayward Fault. Two of the largest earthquakes in recent history were the 1906 San Francisco earthquake and the 1989 Loma Prieta earthquake . The Bay Area
3318-523: A single San Francisco-based bank failed, while the region attempted to spur job growth by simultaneously undertaking two large infrastructure projects: construction of the Golden Gate Bridge , which would connect San Francisco with Marin County , and the Bay Bridge , which would connect San Francisco with Oakland and the East Bay. After the United States joined World War II in 1941, the Bay Area became
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#17330853427263476-607: A single county, Alameda. Diverse assemblages adjoin in complex arrangements due to offsets along the many faults (both active and stable) in the area. As a consequence, many types of rock and soil are found in the region. The oldest rocks are metamorphic rocks that are associated with granite in the Salinian Block west of the San Andreas Fault . These were formed from sedimentary rocks of sandstone , limestone , and shale in uplifted seabeds. Volcanic deposits also exist in
3634-436: A single line. When calling a party, the operator used code ringing, a distinctive ringing signal sequence, such as two long rings followed by one short ring. Everyone on the line could hear the signals, and could pick up and monitor other people's conversations. Automatic exchanges , which provided dial service , were invented by Almon Strowger in 1888. First used commercially in 1892, they did not gain widespread use until
3792-410: A stampede of wealth-seekers descending on Sutter's Mill . The Bay Area's population quickly emptied out as laborers, clerks, waiters, and servants joined the rush to find gold, and California's first newspaper, The Californian , was forced to announce a temporary freeze in new issues due to labor shortages. By the end of 1849, news had spread across the world and newcomers flooded into the Bay Area at
3950-583: A startup opportunity that had been presented to Don by Venture Capitalist (VC) business associates. Two entrepreneurs had approached the VCs with a business opportunity with the Regional Bell Operating Companies (RBOC). The RBOCs had recently gone through divestiture from AT&T in 1984 and were looking at their future without Bell Labs. They had worked for Pacific Bell and a consulting company who Pacific Bell had hired to study their future strategy in
4108-649: A storm sank the San Agustin and killed between 7 and 12 people. On December 8, 80 remaining crew members set sail on the San Buenaventura , a launch which was partially constructed en route from the Philippines . Seeking the fastest route south, the expedition sailed past the Golden Gate, arriving at Puerto de Chacala, Mexico on January 17, 1596. The Bay Area estuaries remained unknown to Europeans until members of
4266-457: A telephone with a dial tone . Telecommunication carriers also define rate centers for business and billing purposes, which in large cities, might encompass clusters of central offices to specify geographic locations for distance measurement calculations. In the 1940s, the Bell System in the United States and Canada introduced a nationwide numbering system that identified central offices with
4424-463: A trunk as idle. Trunk circuitry hearing a 2,600 Hz tone for a certain duration would go idle. (The duration requirement reduced falsing .) Some systems used tone frequencies over 3,000 Hz, particularly on SSB frequency-division multiplex microwave radio relays . On T-carrier binary digital transmission systems, bits within the T-1 data stream were used to transmit supervision. By careful design,
4582-476: A unique three-digit code, along with a three-digit numbering plan area code (NPA code or area code), making central office codes distinctive within each numbering plan area. These codes served as prefixes in subscriber telephone numbers. The mid-20th century saw similar organizational efforts in telephone networks globally, propelled by the advent of international and transoceanic telephone trunks and direct customer dialing. For corporate or enterprise applications,
4740-525: A very high level presentation of a system design to the VCs. Since it had been many years since Don was involved in system design, he asked Tom to meet with them for a presentation to evaluate their ideas at a hotel at the San Francisco Airport. Most of the presentation was slides taken from the consulting report reviewing the macro-opportunity followed by some simplistic architecture concept slides. Tom had just completed architecture and design work on
4898-466: A who's who in the telecom equipment supplier world and includes Cisco , Alcatel, Alcatel-Lucent , Nokia, Motorola, DSC, Tellabs , General Instrument, Force10, Meriton and others. The term has now fallen out of common use in Sonoma County after the market, and specifically high tech or dot-com bubble collapse of early 2000. According to the market research firm RHK in 2003, Alcatel continued to hold
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5056-402: A year later. In 1887 Puskás introduced the multiplex switchboard . . Later exchanges consisted of one to several hundred plug boards staffed by switchboard operators . Each operator sat in front of a vertical panel containing banks of ¼-inch tip-ring-sleeve (3-conductor) jacks, each of which was the local termination of a subscriber 's telephone line . In front of the jack panel lay
5214-751: Is accepted by most local governmental agencies including San Francisco Regional Water Quality Control Board , Bay Area Air Quality Management District , the San Francisco Bay Restoration Authority , the Metropolitan Transportation Commission , and the Association of Bay Area Governments , the latter two of which partner to deliver a Bay Area Census using the nine-county definition. Various U.S. Federal government agencies use definitions that differ from their local counterparts' nine-county definition. For example,
5372-403: Is additionally known for the complexity of its landforms, the result of millions of years of tectonic plate movements. Because the Bay Area is crossed by six major earthquake faults , the region is particularly exposed to hazards presented by large earthquakes. The climate is temperate and conducive to outdoor recreational and athletic activities such as hiking, running, and cycling. The Bay Area
5530-820: Is home to a complex network of watersheds, marshes, rivers, creeks, reservoirs, and bays that predominantly drain into the San Francisco Bay and Pacific Ocean. The largest bodies of water in the Bay Area are the San Francisco , San Pablo , and Suisun estuaries. Major rivers of the North Bay include the Napa River , the Petaluma River , the Gualala River , and the Russian River ; the former two drain into San Pablo Bay ,
5688-468: Is host to five professional sports teams and is a cultural center for music, theater, and the arts. It is also host to numerous higher education institutions, including research universities such as the University of California, Berkeley , and Stanford University , the latter known for helping to create the high tech center called Silicon Valley . Home to 101 municipalities and 9 counties, governance in
5846-463: Is largely influenced by the cold California Current , which penetrates the natural mountainous barrier along the coast by traveling through various gaps. In terms of precipitation , this means that the Bay Area has pronounced seasons. The winter season, which roughly runs between November and March, is the source of about 82% of annual precipitation in the area. In the South Bay and further inland, while
6004-517: Is viewed as the main branch which led to the many subsequent telecom equipment suppliers that was part of the genesis of term Telecom Valley. In 1984, the Bell System divestiture created the 7 Regional Bell Operating Company (RBOC) structure that were no longer constrained to placing AT&T's Bell Labs and Western Electric products in their networks. This created a multibillion-dollar market opportunity for new equipment suppliers including DLCs. It
6162-581: The Bank of Italy (now known as the Bank of America ), had managed to retrieve the money from his bank's vaults before fires broke out through the city and was the only bank with liquid funds readily available and was instrumental in loaning out funds for rebuilding efforts. Congress immediately approved plans for a reservoir in Hetch Hetchy Valley in Yosemite National Park , a plan they had denied
6320-628: The Bay Area , is a region of California surrounding and including San Francisco Bay , and anchored by the cities of San Francisco , Oakland , and San Jose . The Association of Bay Area Governments defines the Bay Area as including the nine counties that border the estuaries of San Francisco Bay, San Pablo Bay , and Suisun Bay : Alameda , Contra Costa , Marin , Napa , San Mateo , Santa Clara , Solano , Sonoma , and San Francisco . Other definitions may be either smaller or larger, and may include neighboring counties which are not officially part of
6478-409: The Bell System stated that customers in large cities should not need to be concerned with the type of office, whether they were calling a manual or an automatic office. When a subscriber dialed the number of a manual station, an operator at the destination office answered the call after seeing the number on an indicator , and connected the call by plugging a cord into the outgoing circuit and ringing
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6636-706: The Bell Telephone Company in Boston in 1877. The world's first state-administered telephone exchange opened on November 12, 1877 in Friedrichsberg close to Berlin under the direction of Heinrich von Stephan . George W. Coy designed and built the first commercial US telephone exchange which opened in New Haven, Connecticut in January, 1878, and the first telephone booth was built in nearby Bridgeport . The switchboard
6794-602: The Federal Communications Commission (FCC) which regulates broadcast, cable, and satellite transmissions, includes nearby Colusa , Lake and Mendocino counties in their " San Francisco - Oakland - San Jose " media market , but excludes eastern Solano County. On the other hand, the United States Office of Management and Budget , which designates metropolitan statistical areas (MSAs) and combined statistical areas (CSA) for populated regions across
6952-582: The Golden Gate or the estuaries, likely due to fog. Sir Francis Drake became the first European to land in the area and claim it in June 1579, when he landed at Drakes Bay near Point Reyes. Even though he claimed the region for Queen Elizabeth I as Nova Albion or New Albion , the English made no immediate follow up to the claim. In 1595, Philip II of Spain tasked Sebastião Rodrigues Soromenho with mapping
7110-680: The Hayward Fault Zone , Concord-Green Valley Fault , Calaveras Fault , Clayton-Marsh Creek-Greenville Fault , Rodgers Creek Fault , and the San Gregorio Fault . Significant blind thrust faults (faults with near vertical motion and no surface ruptures) are associated with portions of the Santa Cruz Mountains and the northern reaches of the Diablo Range and Mount Diablo . These "hidden" faults, which are not as well known, pose
7268-636: The Hayward fault , and the Diablo Range , which includes Mount Diablo and Mount Hamilton and runs along the Calaveras fault . In total, the Bay Area is traversed by seven major fault systems with hundreds of related faults, all of which are stressed by the relative motion between the Pacific Plate and the North American Plate or by compressive stresses between these plates. The fault systems include
7426-511: The Internet in the middle of the decade rapidly created a speculative bubble in the high-tech economy known as the dot-com bubble . This bubble began collapsing in the early 2000s and the industry continued contracting for the next few years, nearly wiping out the market. Companies like Amazon.com and Google managed to weather the crash however, and following the industry's return to normalcy, their market value increased significantly. Even as
7584-604: The North Pacific High through the Golden Gate, which creates the city's characteristic cool winds and fog . The microclimate phenomenon is most pronounced during this time, when fog penetration is at its maximum in areas near the Golden Gate strait, while the South Bay and areas further inland are sunny and dry. Along the San Francisco peninsula, gaps in the Santa Cruz Mountains , one south of San Bruno Mountain and another in Crystal Springs, allow oceanic weather into
7742-539: The Pacific Ocean on the west and the bay on the east and are characterized by their mountainous and woody terrain. Sonoma and Napa counties are known internationally for their grape vineyards and wineries , and Solano County to the east, centered around Vallejo , is the fastest growing region in the Bay Area. The " Peninsula " subregion includes the cities and towns on the San Francisco Peninsula, excluding
7900-598: The Portolá expedition , while trekking along the California coast, encountered them in 1769 when the Golden Gate blocked their continued journey north. Several missions were founded in the Bay Area during this period. In 1806, a Spanish expedition led by Gabriel Moraga began at the Presidio, traveled south of the bay, and then east to explore the San Joaquin Valley . In 1821, Mexico gained its independence from Spain and
8058-583: The San Joaquin River Delta , causing a cooling effect in Stockton and Sacramento , so that these cities are also cooler than their Central Valley counterparts in the south. The Bay Area is home to a diverse array of wildlife and, along with the connected San Joaquin River Delta represents one of California's most important ecological habitats. California's Dungeness crab , Pacific halibut , and
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#17330853427268216-658: The USS ; Portsmouth into the bay and seized San Francisco, which was then known as Yerba Buena , and raised the American flag for the first time over Portsmouth Square . In 1848, James W. Marshall 's discovery of gold in the American River sparked the California Gold Rush , and within half a year 4,000 men were panning for gold along the river and finding $ 50,000 per day. The promise of fabulous riches quickly led to
8374-610: The University of California, Berkeley Richard Walker claimed that "no other U.S. city-region is as definitionally challenged [as the Bay Area]." When the region began to rapidly develop during and immediately after World War II , local planners settled on a nine-county definition for the Bay Area, consisting of the counties that directly border the San Francisco , San Pablo , and Suisun estuaries : Alameda , Contra Costa , Marin , Napa , San Francisco , San Mateo , Santa Clara , Solano , and Sonoma counties. Today, this definition
8532-462: The Western Electric 1ESS switch , Northern Telecom SP1 , Ericsson AXE, Automatic Electric EAX-1 & EAX-2, Philips PRX /A, ITT Metaconta, British GPO/BT TXE series and several other designs were similar. Ericsson also developed a fully computerized version of their ARF crossbar exchange called ARE. These used a crossbar switching matrix with a fully computerized control system and provided
8690-546: The crossbar switch . Circuits interconnecting switches are called trunks . Before Signalling System 7 , Bell System electromechanical switches in the United States originally communicated with one another over trunks using a variety of DC voltages and signaling tones. Today, those simple digital signals have been replaced by more modern coded digital signals (typically using binary code). Some signaling communicated dialed digits. An early form called Panel Call Indicator Pulsing used quaternary pulses to set up calls between
8848-485: The gay rights movement . At the same time, parts of San Mateo and Santa Clara counties began to rapidly develop from an agrarian economy into a hotbed of the high-tech industry . Fred Terman , the director of a top-secret research project at Harvard University during World War II, joined the faculty at Stanford University in order to reshape the university's engineering department. His students, including David Packard and William Hewlett , would later help usher in
9006-466: The osprey . In 1927, zoologist Joseph Grinnell wrote that osprey were only rare visitors to the San Francisco Bay Area, although he noted records of one or two used nests in the broken tops of redwood trees along the Russian River . In 1989, the southern breeding range of the osprey in the Bay Area was Kent Lake , although osprey were noted to be extending their range further south in
9164-415: The telephone when the user removes the handset from the switchhook or cradle. The exchange provides dial tone at that time to indicate to the user that the exchange is ready to receive dialed digits. The pulses or DTMF tones generated by the telephone are processed and a connection is established to the destination telephone within the same exchange or to another distant exchange. The exchange maintains
9322-561: The west coast of the United States , including populations residing in tributaries to San Francisco Bay. California Coast Chinook salmon were historically native to the Guadalupe River in San Francisco Bay, and Chinook salmon runs persist today in the Guadalupe River, Coyote Creek , Napa River , and Walnut Creek . Industrial, mining, and other uses of mercury have resulted in a widespread distribution of that poisonous metal in
9480-563: The 1980s an effort to re-introduce the species to the area began with the Santa Cruz Predatory Bird Research Group and the San Francisco Zoo importing birds and eggs from Vancouver Island and northeastern California, and there are now nineteen nesting couples in eight of the Bay Area's nine counties. Other once absent species that have returned to the Bay Area include Swainson's hawk , white tailed kite , and
9638-621: The AT&;T 5ESS and Northern Telecom DMS-100 from a slave subtending DLC. That meant the switching equipment suppliers could not monopolize the DLC due to the opening of the interface to other equipment suppliers. This made the nearly $ 2B DLC market a key telecom equipment product target. In the same mid-1980s time frame, the ANSI T1 standards body began defining a new fiber optic interface standard that came to be known as SONET or Synchronous Optical Networking in
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#17330853427269796-885: The Access Network between the Central Office and customer premises. This consulting report had envisioned the future need for fiber in the Telco Access Network and described broadly an integrated and intelligent fiber terminal to replace the existing fiber multiplexing equipment and the Digital Loop Carrier (DLC). It further envisioned integration of work being done at Bellcore who was the RBOC's new research group derived from Bell Labs. It suggested it must have dramatically enhanced integration, bandwidth, intelligence, standards compliance and performance. These entrepreneurs had made
9954-441: The Americas . The earliest Spanish exploration of the Bay Area took place in 1769. The Mexican government controlled the area from 1821 until the 1848 Treaty of Guadalupe Hidalgo . Also in 1848, James W. Marshall discovered gold in nearby mountains , resulting in explosive immigration to the area and the precipitous decline of the Native population . The California Gold Rush brought rapid growth to San Francisco . California
10112-416: The Bay Area at the time of first European contact were descended from Siberian tribes who arrived at around 1,000 BCE by sailing over the Arctic Ocean and following the salmon migration. However the current academic consensus is compatible with the oral tradition of the Ohlone and Miwok peoples, which suggests they have been living in the Bay Area for several hundreds if not thousands of years. At
10270-439: The Bay Area became part of the Mexican province of Alta California , a period characterized by ranch life and visiting American trappers. Mexico's control of the territory would be short-lived, however, and in 1846 a party of settlers occupied Sonoma Plaza and proclaimed the independence of the new Republic of California . That same year, the Mexican–American War began, and American captain John Berrien Montgomery sailed
10428-449: The Bay Area has experienced numerous political, cultural, and artistic movements, developing unique local genres in music and art and establishing itself as a hotbed of progressive politics . Economically, the post-war Bay Area saw large growth in the financial and technology industries, creating an economy with a gross domestic product of over $ 700 billion. In 2018 it was home to the third-highest concentration of Fortune 500 companies in
10586-402: The Bay Area involves numerous local and regional jurisdictions, often with broad and overlapping responsibilities. The Coyote Hills Shell Mound, the earliest known archaeological evidence of human habitation of the Bay Area estuaries, dates to around 10,000 BCE, with evidence pointing to even earlier settlement in Point Reyes in Marin County . It has been conjectured that the people living in
10744-509: The Bay Area their home, making the region a popular destination for birdwatching . Many birds are listed as endangered species despite once being common in the region. Western burrowing owls were originally listed as a species of special concern by the California Department of Fish and Game in 1979. California's population declined 60% from the 1980s to the early 1990s, and continues to decline at roughly 8% per year. A 1992–93 survey reported little to no breeding burrowing owls in most of
10902-434: The Bay Area, all naturally spawned anadromous steelhead populations below natural and manmade impassable barriers in California streams from the Russian River to Aptos Creek , and the drainages of San Francisco, San Pablo, and Suisun Bays are listed as threatened under the Federal Endangered Species Act . The Central California Coast coho salmon population is the most endangered of the many troubled salmon populations on
11060-420: The Bay Area, left behind by the movement of the San Andreas Fault, whose movement sliced a subduction plate and allowed magma to briefly flow to the surface. The region has considerable vertical relief in its landscapes that are not in the alluvial plains leading to the bay or in the inland valleys. The topography, and geologic history, of the Bay Area can largely be attributed to the compressive forces between
11218-420: The Bay Area: the Karkin of the Carquinez Strait , the Chochenyo of the East Bay , the Ramaytush of the San Francisco Peninsula , and the Tamien of the South Bay. The Miwok had two major groups in the Bay Area: the Bay Miwok of Contra Costa and the Coast Miwok of Marin and Sonoma . In 1542, Juan Rodríguez Cabrillo explored the Pacific coast near the Bay Area though the expedition did not see
11376-504: The Bay. The wild turkey population was introduced in the 1960s by state game officials, and by 2015 have become a common sight in East Bay communities. The Bay Area is well known for the complexity of its landforms that are the result of the forces of plate tectonics acting over of millions of years, since the region is located in the middle of a meeting point between two plates. Nine out of eleven distinct assemblages have been identified in
11534-409: The Bell System required continuous maintenance, such as cleaning. Indicator lights on equipment bays alerted staff to conditions such as blown fuses (usually white lamps) or a permanent signal (stuck off-hook condition, usually green indicators). Step offices were more susceptible to single-point failures than newer technologies. Crossbar offices used more shared, common control circuits. For example,
11692-414: The Bell System. Electronic switching systems gradually evolved in stages from electromechanical hybrids with stored program control to the fully digital systems. Early systems used reed relay -switched metallic paths under digital control. Equipment testing, phone numbers reassignments, circuit lockouts and similar tasks were accomplished by data entry on a terminal. Examples of these systems included
11850-480: The California scorpionfish are all significant components of the bay's fisheries . The bay's salt marshes now represent most of California's remaining salt marsh and support a number of endangered species and provide key ecosystem services such as filtering pollutants and sediments from the rivers. Most famously, the bay is a key link in the Pacific Flyway and with millions of shorebirds annually visiting
12008-724: The Central Valley and the Sierra Nevada. In 2014, a Bay Area-wide survey found osprey had extended their breeding range southward with nesting sites as far south as Hunters Point in San Francisco on the west side and Hayward on the east side, while further studies have found nesting sites as far south as the Los Gatos Creek watershed, indicating that the nesting range now includes the entire length of San Francisco Bay. Most nests were built on man-made structures close to areas of human disturbance, likely due to lack of mature trees near
12166-635: The East Bay receives oceanic weather that travels through the Golden Gate strait, and further diffuses that air through the Berkeley Hills , Niles Canyon and the Hayward Pass into the Livermore Valley and Altamont Pass . Here, the resulting breeze is so strong that it is home to one of the world's largest array of wind turbines . Further north, the Carquinez Strait funnels the ocean weather into
12324-643: The GR-303 specification and former Bell Labs Department Head responsible for planning the SLC-5 DLC System for AT&T. Hawley created the Optilink product road map that Ehreth, Eames, and Malloy developed. Known as the Litespan-2000, this system came to define the class of products known as Next Generation Digital Loop Carrier Systems or NGDLC. This interface decoupled Telephone Exchange or Switching Systems such as
12482-587: The H20/20 Digital PABX. Both the market opportunity and a vision of the implementation seemed obvious in the H20/20 experience context. It was also clear the entrepreneurs had little system design experience. Tom returned from the meeting, and reported to Don that this was an intriguing and fabulous opportunity and the DTS H20/20 team already had most of the expertise to realize the vision. Don returned this report to
12640-510: The Optilink NGDLC by all 7 RBOCs plus the large independent GTE . Optilink was acquired by the mid-sized DSC Communications of Plano, Texas in 1990, which was later purchased by the large French multinational telecom supplier Alcatel who then merged in 2006 with the Bell Labs child Lucent forming Alcatel-Lucent . DSC and Alcatel together drove Optilink's Litespan 2000 NGDLC sales to one of
12798-769: The Pacific Plate and the North American plate. The three major ridge structures in the Bay Area, part of the Pacific Coast Range , are all roughly parallel to the major faults . The Santa Cruz Mountains along the San Francisco Peninsula and the Marin Hills in Marin County follow the San Andreas fault , The Berkeley Hills , San Leandro Hills and their southern ridgeline extension through Mission Peak roughly follow
12956-413: The San Francisco Bay Area are not officially delineated, and the unique development patterns influenced by the region's topography , as well as unusual commute patterns caused by the presence of three central cities and employment centers located in various suburban locales, has led to considerable disagreement between local and federal definitions of the area. Because of this, professor of geography at
13114-526: The San Francisco Bay Area, such as the Central Coast counties of Santa Cruz , San Benito , and Monterey , or the Central Valley counties of San Joaquin , Merced , and Stanislaus . The Bay Area is known for its natural beauty, prominent universities, technology companies, and affluence. The Bay Area contains many cities, towns, airports, and associated regional, state, and national parks, connected by
13272-469: The Strowger's typical 10 pps—typically about 20 pps. At a later date many also accepted DTMF "touch tones" or other tone signaling systems. A transitional technology (from pulse to DTMF) had converters to convert DTMF to pulse, to feed to older Strowger, panel, or crossbar switches. This technology was used as late as mid-2002. Many terms used in telecommunication technology differ in meaning and usage among
13430-546: The US. Optilink was formed to develop a Next Generation Digital Loop Carrier (NGDLC) targeted at the Bell System and was partly based on the combination of Telcordia GR-303 and SONET integrated into a more advanced DLC. The Optilink architecture that combined Telcordia GR-303 and the ANSI standard SONET then became the de facto definition of the NGDLC. This in turn led to acceptance and deployment of
13588-531: The United States. The Bay Area is home to approximately 7.52 million people. The larger federal classification, the combined statistical area of the region which includes 13 counties, is the second-largest in California—after the Greater Los Angeles area—and the fifth-largest in the United States, with over 9 million people. The Bay Area's population is ethnically diverse: roughly three-fifths of
13746-517: The VCs and Optilink was soon born. Don Green along with a management and the key technical team from Harris Digital Telephone Systems founded Optilink in Petaluma, California in 1987. Green's co-founder was Al Negrin. Key early employees in addition to Eames were Dave Ehreth who was Director of Engineering, Dave Malloy who led the software development and Chet Stephens who was the first VP of Sales. All were former employees of Green's at Harris. Optilink
13904-484: The Whale , a humpback whale who entered San Francisco Bay twice on errant migrations in the late 1980s and early 1990s. Bottlenose dolphins and harbor porpoises have recently returned to the bay, having been absent for many decades. Historically, this was the northern extent of their warm-water species range. In addition to the many species of marine birds that can be seen in the Bay Area, many other species of birds make
14062-471: The appropriated bits did not change voice quality appreciably. Robbed bits were translated to changes in contact states (opens and closures) by electronics in the channel bank hardware. This allowed direct current E and M signaling, or dial pulses, to be sent between electromechanical switches over a pure digital carrier which did not have DC continuity. Bell System installations typically had alarm bells, gongs, or chimes to announce alarms calling attention to
14220-472: The area's largest city and the 13th-most populous in the United States . Despite its urban character, San Francisco Bay is one of California's most ecologically sensitive habitats, providing important ecosystem services such as filtering the pollutants and sediments from rivers and supporting a number of endangered species . In addition, the Bay Area is known for its stands of coast redwoods , many of which are protected in state and county parks. The region
14378-407: The automation of telephone circuit switching. While there were many extensions and adaptations of this initial patent, the one best known consists of 10 levels or banks, each having 10 contacts arranged in a semicircle. When used with a rotary telephone dial , each pair of digits caused the shaft of the central contact "hand" of the stepping switch to first step (ratchet) up one level for each pulse in
14536-590: The bay has been significantly altered heavily re-engineered to accommodate the needs of water delivery, shipping, agriculture, and urban development, with side effects including the loss of wetlands and the introduction of contaminants and invasive species . Approximately 85% of those marshes have been lost or destroyed, but about 50 marshes and marsh fragments remain. Huge tracts of the marshes were originally destroyed by farmers for agricultural purposes, then repurposed to serve as salt evaporation ponds to produce salt for food and other purposes. Today, regulations limit
14694-436: The bay into north and south regions. In 1989, the federal Environmental Protection Agency defined the South Bay as the northern part of Santa Clara County and the southeastern part of San Mateo County. The Bay Area is located in the warm-summer Mediterranean climate zone ( Köppen Csb ) that is a characteristic of California's coast, featuring mild to cool winters with occasional rainfall, and warm to hot, dry summers. It
14852-496: The bay shallows as a refuge, is the most important component of the flyway south of Alaska . Many endangered species of birds are also found here: the California least tern , the California clapper rail , the snowy egret , and the black crowned night heron . There is also a significant diversity of salmonids present in the bay. Steelhead populations in California have dramatically declined due to human and natural causes; in
15010-479: The bay, with uptake in the bay's phytoplankton and contamination of its sportfish . Aquatic mammals are also present in the bay. Before 1825, Spanish, French, English, Russians and Americans were drawn to the Bay Area to harvest prodigious quantities of beaver , river otter , marten, fisher, mink, fox, weasel, harbor and fur seals and sea otter . This early fur trade, known as the California Fur Rush ,
15168-468: The call only if intermediate trunk lines were available between all the centers at the same time. In 1943 when military calls had priority, a cross-country US call might take as long as 2 hours to request and schedule in cities that used manual switchboards for toll calls. On March 10, 1891, Almon Brown Strowger , an undertaker in Kansas City, Missouri , patented the stepping switch , a device which led to
15326-533: The capital city moved between three cities in the Bay Area: San Jose (1849–1851), Vallejo (1851–1852), and Benicia (1852–1853) before permanently settling in Sacramento in 1854. As the Gold Rush subsided, wealth generated from the endeavor led to the establishment of Wells Fargo Bank and the Bank of California , and immigrant laborers attracted by the promise of wealth transformed the demographic makeup of
15484-437: The circuit, allowing them to handle another call, while the caller heard an audible ringback signal, so that that operator would not have to periodically report that they were continuing to ring the line. In the ringdown method, the originating operator called another intermediate operator who would call the called subscriber, or passed it on to another intermediate operator. This chain of intermediate operators could complete
15642-553: The city of San Francisco, natural and artificial topographical features direct the movement of wind and fog, resulting in startlingly varied climates between city blocks. Along the Golden Gate Strait , oceanic wind and fog from the Pacific Ocean are able to penetrate the mountain barriers inland into the Bay Area. During the summer, rising hot air in California's interior valleys creates a low pressure area that draws winds from
15800-581: The coining of the term Telecom Valley due to the high density of telecom equipment suppliers in one small 10 mile corridor in Sonoma County . Nearly all the telecom startups in Telecom Valley were acquired by larger companies with life cycles similar to the original DTS->Farinon->Harris and Optilink->DSC->Alcatel acquisition legacies. In fairly recent times, even the successful Turin Networks has merged with Force10 Networks in 2009 while Mahi Networks
15958-419: The connection until one of the parties hangs up. This monitoring of connection status is called supervision. Additional features, such as billing equipment, may also be incorporated into the exchange. The Bell System dial service implemented a feature called automatic number identification (ANI) which facilitated services like automated billing, toll-free 800-numbers , and 9-1-1 service. In manual service,
16116-494: The country, has five MSAs which include, wholly or partially, areas within the nine-county definition, and one CSA which includes eight Bay Area counties (excluding Sonoma ), but including neighboring San Benito , Santa Cruz , San Joaquin , Merced , and Stanislaus counties. The Association of Bay Area Health Officers (ABAHO), an organization that has fought local outbreaks of HIV/AIDS in 1980s and with COVID-19 pandemic and Delta cron hybrid variant (2020–22), consists of
16274-533: The crank to generate ringing current. The switchboard responded by interrupting the circuit, which dropped a metal tab above the subscriber's line jack and sounded a buzzer. Dry cell batteries, normally two large N°. 6 cells in the subscriber's telephone, provided the direct current for the transmitter. Such magneto systems were in use in the US as late as 1983, as in the small town, Bryant Pond, Woodstock, Maine . Many small town magneto systems featured party lines , anywhere from two to ten or more subscribers sharing
16432-468: The destination station. For example, if a dial customer calling from TAylor 4725 dialed a number served by a manual exchange, e.g., ADams 1383-W, the call was completed, from the subscriber's perspective, exactly as a call to LEnnox 5813, in an automated exchange. The party line letters W, R, J, and M were only used in manual exchanges with jack-per-line party lines. In contrast to the listing format MAin 1234 for an automated office with two capital letters,
16590-490: The destruction of tidal marshes, and large portions are currently being rehabilitated to their natural state. Over time, droughts and wildfires have increased in frequency and become less seasonal and more year-round, further straining the region's water security . According to the 2010 United States Census , the population of the nine-county Bay Area was 7.15 million, with 49.6% male and 50.4% female. Of these, approximately 2.3 million (32%) are foreign born. In 2010
16748-473: The enterprise. In the era of the electrical telegraph, its principal users were post offices, railway stations, the more important governmental centers (ministries), stock exchanges, very few nationally distributed newspapers, the largest internationally important corporations, and wealthy individuals. Despite the fact that telephone devices existed before the invention of the telephone exchange, their success and economical operation would have been impossible on
16906-486: The faster pulsing rate made trunk utilization more efficient because the switch spent half as long listening to digits. DTMF was not used for trunk signaling. Multi-frequency (MF) was the last of the pre-computerized methods. It used a different set of tones sent in pairs like DTMF. Dialing was preceded by a special keypulse (KP) signal and followed by a start (ST). Variations of the Bell System MF tone scheme became
17064-435: The first decade of the 20th century. They eliminated the need for human switchboard operators who completed the connections required for a telephone call . Automation replaced human operators with electromechanical systems, and telephones were equipped with a dial by which a caller transmitted the destination telephone number to the automatic switching system. A telephone exchange automatically senses an off-hook condition of
17222-424: The first digit and then to swing horizontally in a contact row with one small rotation for each pulse in the next digit. Later stepping switches were arranged in banks, the first stage of which was a linefinder . If one of up to a hundred subscriber lines (two hundred lines in later linefinders) had the receiver lifted "off hook", a linefinder connected the subscriber's line to a free first selector, which returned
17380-399: The front cord of the pair ( ringing cord ) into the called party's local jack and started the ringing cycle. For a long-distance call, the operator plugged into a trunk circuit to connect to another operator in another bank of boards or at a remote central office. In 1918, the average time to complete the connection for a long-distance call was 15 minutes. Early manual switchboards required
17538-549: The growth of the technology sector transformed the region's economy, progressive politics continued to guide the region's political environment. By the turn of the millennium, non-Hispanic whites , the largest ethnic group in the United States, were only half of the population in the Bay Area as immigration among minority groups accelerated. During this time, the Bay Area was the center of the LGBT rights movement : in 2004, San Francisco began issuing marriage licenses to same-sex couples ,
17696-566: The hit American pop song San Francisco (Be Sure to Wear Flowers in Your Hair) further enticing like-minded individuals to join the movement in the Bay Area and leading to the Summer of Love . In the proceeding decades, the Bay Area would cement itself as a hotbed of New Left activism, student activism , opposition to the Vietnam War and other anti-war movements , the black power movement , and
17854-404: The impetus for the creation of a new industrial sector. As with the invention of the telephone itself, the honour of "first telephone exchange" has several claimants. One of the first to propose a telephone exchange was Hungarian Tivadar Puskás in 1877 while he was working for Thomas Edison . The first experimental telephone exchange was based on the ideas of Puskás, and it was built by
18012-511: The interior, causing a cooling effect for cities along the Peninsula and even as far south as San Jose. This weather pattern is also the source for delays at San Francisco International Airport . In Marin county north of the Golden Gate strait, two gaps north of Muir Woods bring cold air across the Marin Headlands , with the cooling effect reaching as far north as Santa Rosa . Further inland,
18170-408: The larger subregions, the East Bay includes a variety of enclaves, including the suburban Tri-Valley area and the highly urban western part of the subregion that runs alongside the bay, including Oakland. The " North Bay " includes Marin , Sonoma , Napa , and Solano counties, and is the geographically largest and least populated subregion. The western counties of Marin and Sonoma are encased by
18328-481: The largest deployments in telecom system's history with its telephone lines served crossing the 50 million mark in 2000 according to Alcatel in 2003. Telecom Valley might also be referred to as DLC Valley since its lineage began the market assault on the Bell System SLC-96 DLC market dominance in 1969 at DTS, then won a dominant position through Optilink and Advanced Fibre Communications (now Tellabs ) and now
18486-408: The latter term originating from the Bell System . A central office typically refers to a facility that houses the inside plant equipment for one or several telephone exchanges, each catering to a specific geographical region. This region is sometimes known as the exchange area. In North America, the term wire center may be used to denote a central office location, indicating a facility that provides
18644-429: The latter two into the Pacific Ocean. In the South Bay, the Guadalupe River drains into San Francisco Bay near Alviso . There are also several lakes present in the Bay Area, including man-made lakes like Lake Berryessa and natural albeit heavily modified lakes like Lake Merritt . Prior to the introduction of European agricultural methods, the shores of San Francisco Bay consisted mostly of tidal marshes. Today,
18802-721: The market in 2003, plus the highly successful AFC/ Tellabs UMC family and now the Calix very advanced broadband family combined will never be surpassed by another area. There have been numerous spin offs, acquisitions, startups and even IPOs that either directly or indirectly derived from DTS or Optilink in Telecom Valley's ever branching history. They have included: Telenetworks, Diamond Lane Communications, Advanced Fibre Communications, Next Level Communications, Fibex Systems, Fiberlane/Cerent, Mahi Networks , Calix , Turin Networks (now Dell ), Dilithium Networks , Teknovus (now Broadcom ), Cyan Optics along with many others. They collectively led to
18960-583: The most ethnically diverse cities in the United States. Telephone Exchange A telephone exchange , also known as a telephone switch or central office , is a crucial component in the public switched telephone network (PSTN) or large enterprise telecommunications systems. It facilitates the interconnection of telephone subscriber lines or digital system virtual circuits, enabling telephone calls between subscribers. The terminology used in telecommunications has evolved over time, with telephone exchange and central office often used interchangeably,
19118-399: The number is in the same central office, and located on the operator's switchboard, the operator connects the call by plugging the ringing cord into the jack corresponding to the called customer's line. If the called party's line is on a different switchboard in the same office, or in a different central office, the operator plugs into the trunk for the destination switchboard or office and asks
19276-476: The number of digit receivers needed in a switch. Every task in electromechanical switches was done in big metallic pieces of hardware. Every fractional second cut off of call set up time meant fewer racks of equipment to handle call traffic. Examples of signals communicating supervision or call progress include E and M signaling , SF signaling, and robbed-bit signaling. In physical (not carrier) E and M trunk circuits, trunks were four wire. Fifty trunks would require
19434-432: The operator answering (known as the "B" operator) to connect the call. Most urban exchanges provided common-battery service, meaning that the central office provided power to the subscriber telephone circuits for operation of the transmitter, as well as for automatic signaling with rotary dials . In common-battery systems, the pair of wires from a subscriber's telephone to the exchange carry 48V (nominal) DC potential from
19592-538: The operator knows where a call is originating by the light on the switchboard jack field. Before ANI, long-distance calls were placed into an operator queue and the operator asked the calling party's number and recorded it on a paper toll ticket. Early exchanges were electromechanical systems using motors, shaft drives, rotating switches and relays . Some types of automatic exchanges were the Strowger switch or step-by-step switch, All Relay, panel switch , Rotary system and
19750-408: The operator to operate listening keys and ringing keys, but by the late 1910s and 1920s, advances in switchboard technology led to features which allowed the call to be automatically answered immediately as the operator inserted the answering cord, and ringing would automatically begin as soon as the operator inserted the ringing cord into the called party's jack. The operator would be disconnected from
19908-427: The part being worked on as in-use, causing the switching logic to route around it. A similar tool was called a TD tool. Delinquent subscribers had their service temporarily denied (TDed). This was effected by plugging a tool into the subscriber's office equipment on Crossbar systems or line group in step-by-step switches. The subscriber could receive calls but could not dial out. Strowger-based, step-by-step offices in
20066-616: The public health officers of 9 Bay Area counties, in addition to the Central Coast counties of Santa Cruz , San Benito , and Monterey and the city of Berkeley . Among locals, the nine-county Bay Area is divided into five sub-regions: the East Bay , North Bay , Peninsula , city of San Francisco , and South Bay . The " East Bay " is the densest region of the Bay Area outside of San Francisco and includes cities and towns in Alameda and Contra Costa counties centered around Oakland . As one of
20224-497: The racial makeup of the nine-county Bay Area was 52.5% White (42.4% were non-Hispanic and 10.1% were Hispanic ), 23.3% Asian , 6.7% non-Hispanic Black or African American , 0.7% Native American or Alaska Native , 0.6% Pacific Islander , 5.4% from two or more races and 10.8% from other races. Hispanic or Latino residents of any race formed 23.5% of the population. The Bay Area cities of Vallejo , Suisun City , Oakland , San Leandro , Fairfield , and Richmond are among
20382-513: The region and even riots in Oakland. His name was symbolically tied to the Occupy Oakland protests two years later that sought to fight against social and economic inequality. By August 2023, San Francisco was in such severe decline that Mayor Matt Mahan of San Jose joked that one day the region might be renamed the "San Jose Bay Area", after its largest and most prosperous city. The borders of
20540-465: The region's high-tech revolution. In 1955, Shockley Semiconductor Laboratory opened for business in Mountain View near Stanford, and although the business venture was a financial failure, it was the first semiconductor company in the Bay Area, and the talent that it attracted to the region eventually led to a high-tech cluster of companies later known as Silicon Valley . In 1989, in the middle of
20698-412: The region's residents are Hispanic/Latino , Asian , African/Black , Indian , or Pacific Islander , all of whom have a significant presence throughout the region. Most of the remaining two-fifths of the population is non-Hispanic White American . The most populous cities of the Bay Area are San Francisco, Oakland , and San Jose , the latter of which had a population of 969,655 in 2023, making San Jose
20856-557: The region. In the early morning of April 18, 1906, a large earthquake with an epicenter near the city of San Francisco hit the region. Immediate casualty estimates by the U.S. Army 's relief operations were 498 deaths in San Francisco, 64 deaths in Santa Rosa , and 102 in or near San Jose, for a total of about 700. More recent studies estimate the total death count to be over 3,000, with over 28,000 buildings destroyed. Rebuilding efforts began immediately. Amadeo Peter Giannini , owner of
21014-586: The region. Between 1950 and 1960, San Francisco welcomed over 100,000 new residents, inland suburbs in the East Bay saw their populations double, Daly City 's population quadrupled, and Santa Clara 's population quintupled. By the early 1960s, the Bay Area and the rest of Northern California became the center of the counterculture movement . Telegraph Avenue in Berkeley and the Haight-Ashbury neighborhood in San Francisco were seen as centers of activity, with
21172-513: The region. Construction of the First transcontinental railroad from the Oakland Long Wharf attracted so many laborers from China that by 1870, eight percent of San Francisco's population was of Asian origin. The completion of the railroad connected the Bay Area with the rest of the United States, established a truly national marketplace for the trade of goods, and accelerated the urbanization of
21330-637: The reigns are being passed to Calix and their series of broadband DLCs. Telecom Valley has dominated the Digital loop carrier marketplace in the US as few other areas in the world have dominated a major telecom system. Telecom Valley is closing in on having provided one fourth of the US population (over 300 million) with 75 million telephone lines. This achievement will assure the Optilink/DSC/Acatel Litespan families 50 million telephone lines in 2000 plus another 9 years of Litespan sales, still at 34% of
21488-679: The same schema and structure of the contemporary telegraph, as prior to the invention of the telephone exchange switchboard, early telephones were hardwired to and communicated with only a single other telephone (such as from an individual's home to the person's business ). A telephone exchange is a telephone system for a small geographic area that provides the switching (interconnection) of subscriber lines for calls made between them. Telephone exchanges replaced small telephone systems that connected its users with direct lines between each and every subscriber station. Exchanges made telephony an available and comfortable technology for everyday use and it gave
21646-414: The same trunk at the same time. By changing the state of these leads from ground to −48 volts, the switches stepped through a handshake protocol. Using DC voltage changes, the local switch would send a signal to get ready for a call and the remote switch would reply with an acknowledgment (a wink) to go ahead with dial pulsing. This was done with relay logic and discrete electronics. These voltage changes on
21804-625: The sub port of Los Angeles. After World War II, the United Nations was chartered in San Francisco, and in September 1951, the Treaty of San Francisco to re-establish peaceful relations between Japan and the Allied Powers was signed in San Francisco, entering into force a year later. In the years immediately following the war, the Bay Area saw a huge wave of immigration as populations increased across
21962-457: The subscriber a dial tone to show that it was ready to receive dialled digits. The subscriber's dial pulsed at about 10 pulses per second, although the speed depended on the standard of the particular telephone administration. Exchanges based on the Strowger switch were eventually challenged by other exchange types and later by crossbar technology. These exchange designs promised faster switching and would accept inter-switch pulses faster than
22120-400: The telephone company end across the conductors. The telephone presents an open circuit when it is on-hook or idle. When a subscriber's phone is off-hook, it presents an electrical resistance across the line which causes current to flow through the telephone and wires to the central office. In a manually operated switchboard, this current flowed through a relay coil, and actuated a buzzer or
22278-645: The time of colonization, the Ohlone peoples in the Bay Area primarily lived on the San Francisco Peninsula, in the South Bay and in the East Bay, and the Miwok primarily lived in the North Bay, northern East Bay, and Central Valley. Ohlone villages were spread across the Peninsula, East Bay, South Bay, as well as further south into the Monterey Bay area. There were eight major divisions of Ohlone people, four of which were based in
22436-521: The tip of the San Francisco Peninsula, the city of San Francisco is not considered part of the "Peninsula" subregion, but as a separate entity. The term "South Bay" has different meanings to different groups: Writing in 1959 for the Army Corps of Engineers , the United States Department of Commerce defined the South Bay as comprising five counties, corresponding to their two-way division of
22594-491: The titular city of San Francisco. Its eastern half, which runs alongside the Bay, is highly populated, while its less populated western coast traces the coastline of the Pacific Ocean and is known for its open space and hiking trails. Roughly coinciding with the borders of San Mateo County , it also includes the northwestern Santa Clara County cities of Palo Alto , Mountain View , and Los Altos . Although geographically located on
22752-554: The top ranking of 34% with Litespan-2000 sales after 20 years since Optilink's founding. This is a testament to the people and opportunity that led from the legendary DTS then Optilink and eventually over 50 years to all of Telecom Valley. Only the few companies survived while most slowly closed down or moved away after the numerous repeated acquisitions. The legacy of Telecom Valley and its many individuals and companies have now become lore in Sonoma County which lives on today with Don Green viewed as its father. A book written by Don Green
22910-434: The trunk circuit would cause pops or clicks that were audible to the subscriber as the electrical handshaking stepped through its protocol. Another handshake, to start timing for billing purposes, caused a second set of clunks when the called party answered. A second common form of signaling for supervision was called single-frequency or SF signaling . The most common form of this used a steady 2,600 Hz tone to identify
23068-451: The various English speaking regions. For the purpose of this article the following definitions are made: A central office originally was a primary exchange in a city with other exchanges service parts of the area. The term became to mean any switching system including its facilities and operators. It is also used generally for the building that houses switching and related inside plant equipment. In United States telecommunication jargon,
23226-523: The west coast of the Americas. Soromenho set sail on Manila Galleon San Agustin on July 5, 1595 and in early November they reached land between Point St. George and Trinidad Head , north of the Bay Area, in the Lost Coast . The expedition followed the coast southward and on November 7 the San Agustin anchored in Drakes Bay, and claimed the region as Puerto y Bahía de San Francisco . In late November,
23384-419: The western counties in the Bay Area, leaving only Alameda , Contra Costa , and Solano counties as remnants of a once large breeding range. Bald eagles were once common in the Bay Area, but habitat destruction and thinning of eggs from DDT poisoning reduced the California state population to 35 nesting pairs. Bald eagles disappeared from the Bay Area in 1915, and only began returning in recent years. In
23542-459: The winter season is cool and mild, the summer season is characterized by warm sunny days, while in San Francisco and areas closer to the Golden Gate strait, the summer season is periodically affected by fog. Due to the Bay Area's diverse topographic relief (itself the result of the clashing tectonic plates ), the region is home to numerous microclimates that lead to pronounced differences in climate and temperature over short distances. Within
23700-600: Was admitted as the 31st state in 1850. A major earthquake and fire leveled much of San Francisco in 1906. During World War II , the Bay Area played a major role in America's war effort in the Asiatic-Pacific Theater , with the San Francisco Port of Embarkation , of which Fort Mason was one of 14 installations and location of the headquarters, acting as a primary embarkation point for American forces. Since then,
23858-418: Was acquired by Meriton Networks in 2005. Only a few of the Telecom Valley startups remain independent by 2009. They include Cyan and Calix who has taken over the reign of the DLC in Telecom Valley after being started by DTS in 1969 and taken to dominance by Optilink/DSC/ Alcatel-Lucent and then Advanced Fibre Communications/ Tellabs in the early 1990s through the new millennium. The list of parents reads like
24016-592: Was an early innovator in the Telecom Equipment arena developing a Digital loop carrier (DLC) and digital Private Branch Exchange systems. Bell Labs and Western Electric , the R&;D and manufacturing arms of the original AT&T Bell System dominated the DLC markets with the SLC-96 and SLC series 5 systems prior to the 1984 Bell System divestiture . Digital Telephone Systems was purchased by Farinon Corporation which
24174-580: Was built from "carriage bolts, handles from teapot lids and bustle wire" and could handle two simultaneous conversations. Charles Glidden is also credited with establishing an exchange in Lowell, MA. with 50 subscribers in 1878. In Europe other early telephone exchanges were based in London and Manchester , both of which opened under Bell patents in 1879. Belgium had its first International Bell exchange (in Antwerp )
24332-527: Was first reported in Redwood Creek at Muir Beach in 1996, has since been spotted in the North Bay's Corte Madera Creek , the South Bay's Coyote Creek , as well as in 2010 in San Francisco Bay itself at the Richmond Marina . Other mammals include the internationally famous sea lions who began inhabiting San Francisco's Pier 39 after the 1989 Loma Prieta earthquake and the locally famous Humphrey
24490-599: Was more than any other single factor, responsible for opening up the West and the San Francisco Bay Area, in particular, to world trade. By 1817 sea otter in the area were practically eliminated. Since then, the California golden beaver re-established a presence in Alhambra Creek , followed by the Napa River and Sonoma Creek in the north, and the Guadalupe River and Coyote Creek in the south. The North American river otter which
24648-713: Was released in October 2016. Defining Moments is a memoir of Mr. Green's life, beginning in England in the 1930s, then to Canada as a young man, and ultimately to California where he founded four successful telecommunication companies, coining him the "Father of Telecom Valley". George Hawley published a memoir, “Tangled Wires” on Amazon in 2017 that includes some insight into the Optilink story. 38°14′45″N 122°37′53″W / 38.245849°N 122.631276°W / 38.245849; -122.631276 San Francisco Bay Area The San Francisco Bay Area , commonly known as
24806-517: Was subsequently acquired by Harris Corporation of Melbourne, Florida in 1980. Genesis - Prior to the founding of Optilink, Don Green was the CEO of Digital Telephone Systems (DTS) until July 1987. DTS had been acquired twice during Don's tenure, first by Farinon and then again by Harris Corporation. Tom Eames was a principal engineer, manager and system architect at DTS in 1987. In early 1987, Don Green approached Tom and asked him if he would technically evaluate
24964-425: Was this opportunity that was the underlying impetus for the formation of Optilink. The divestiture created a new common RBOC-owned research and engineering company known as Bellcore that began defining its views on the next generation of network technologies including DLCs through its GR-303 interface specification and other documents. Optilink received its initial round of funding after hiring George Hawley, author of
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