title: Alta California

text: Spain also settled the California region with a number of African and mulatto Catholics, including at least ten of the recently re-discovered Los Pobladores, the founders of Los Angeles.


title: Alta California

text: By law, mission land and property were to pass to the indigenous population after a period of about ten years, when the natives would become Spanish subjects. In the interim period, the Franciscans were to act as mission administrators who held the land in trust for the Native residents. The Franciscans, however, prolonged their control over the missions even after control of Alta California passed from Spain to independent Mexico, and continued to run the missions until they were secularized, beginning in 1833. The transfer of property never occurred under the Franciscans.


title: Alta California

text: As the number of Spanish settlers grew in Alta California, the boundaries and natural resources of the mission properties became disputed. Conflicts between the Crown and the Church and between Natives and settlers arose. State and ecclesiastical bureaucrats debated over authority of the missions. The Franciscan priests of Mission Santa Clara de Asís sent a petition to the governor in 1782 which stated that the Mission Indians owned both the land and cattle and represented the Ohlone against the Spanish settlers in nearby San José. The priests reported that Indians' crops were being damaged by the pueblo settlers' livestock and that the settlers' livestock was also "getting mixed up with the livestock belonging to the Indians from the mission" causing losses. They advocated that the Natives be allowed to own property and have the right to defend it.


title: Alta California

text: In 1804, due to the growth of the Spanish population in new northern settlements, the province of Las Californias was divided just south of San Diego, following mission president Francisco Palóu's division between the Dominican and Franciscan jurisdictions. Governor Diego de Borica is credited with defining Alta (upper) and Baja (lower) California's official borders.


title: Alta California

text: The Adams–Onís Treaty of 1819, between the United States and Spain, established the northern limit of Alta California at latitude 42°N, which remains the boundary between the states of California, Nevada and Utah (to the south) and Oregon and Idaho (to the north) to this day. Mexico won independence in 1821, and Alta California became a territory of Mexico the next year.


title: Alta California

text: The Spanish and later Mexican governments rewarded retired "soldados de cuera" with large land grants, known as "ranchos", for the raising of cattle and sheep. Hides and tallow from the livestock were the primary exports of California until the mid-19th century. The construction, ranching and domestic work on these vast estates was primarily done by Native Americans, who had learned to speak Spanish and ride horses. Unfortunately, a large percentage of the population of Native Californians died from European diseases. Under Spanish and Mexican rule the ranchos prospered and grew. "Rancheros" (cattle ranchers) and "pobladores" (townspeople) evolved into the unique Californio culture.


title: Alta California

text: Mexico gained independence from Spain on August 24, 1821, upon conclusion of the decade-long Mexican War of Independence. As the successor state to the Viceroyalty of New Spain, Mexico automatically included the provinces of Alta California and Baja California as territories. Alta California declared allegiance to the new Mexican nation and elected a representative to be sent to Mexico. On November 9, 1822, the first legislature of California was created. With the establishment of a republican government in 1824, Alta California, like many northern territories, was not recognized as one of the constituent States of Mexico because of its small population. The 1824 Constitution of Mexico refers to Alta California as a "territory".


title: Alta California

text: Resentment was increasing toward appointed governors sent from Mexico City, who came with little knowledge of local conditions and concerns. Laws were imposed by the central government without much consideration of local conditions, such as the Mexican secularization act of 1833, causing friction between governors and the people.


title: Alta California

text: In 1836, Mexico repealed the 1824 federalist constitution and adopted a more centralist political organization (under the "Seven Laws") that reunited Alta and Baja California in a single California Department (). The change, however, had little practical effect in far-off Alta California. The capital of Alta California remained Monterey, as it had been since the 1769 Portola expedition first established a military/civil government, and the local political structures were unchanged.


title: Alta California

text: The friction came to a head in 1836, when Monterey-born Juan Bautista Alvarado led a revolt against the 1836 constitution, seizing control of Monterey from Nicolás Gutiérrez. Alvarado's actions nearly led to a civil war with loyalist forces based in Los Angeles, but a ceasefire was arranged. After an unsettled period, Alvarado agreed to support the 1839 constitution, and Mexico City appointed him to serve as governor from 1837 to 1842. Other "Californio" governors followed, including Carlos Antonio Carrillo, and Pío Pico. The last non-Californian governor, Manuel Micheltorena, was driven out after another rebellion in 1845. Micheltorena was replaced by Pío Pico, last Mexican governor of California, who served until 1846 when the U.S. military occupation began.


title: Alta California

text: In the final decades of Mexican rule, American and European immigrants arrived and settled in the former Alta California. Those in Southern California mainly settled in and around the established coastal settlements and tended to intermarry with the Californios. In Northern California, they mainly formed new settlements further inland, especially in the Sacramento Valley, and these immigrants focused on fur-trapping and farming and kept apart from the Californios.


title: Alta California

text: In 1846, following reports of the annexation of Texas to the United States, American settlers in inland Northern California took up arms, captured the Mexican garrison town of Sonoma, and declared independence there as the California Republic. At the same time, the United States and Mexico had gone to war, and forces of the United States Navy entered into Alta California and took possession of the northern port cities of Monterey and San Francisco. The forces of the California Republic, upon encountering the United States Navy and, from them, learning of the state of war between Mexico and the United States, abandoned their independence and proceeded to assist the United States forces in securing the remainder of Alta California. The California Republic was never recognized by any nation and existed for less than one month, but its flag (the "Bear Flag") survives as the flag of the State of California.


title: Alta California

text: After the United States Navy's seizure of the cities of southern California, the Californios formed irregular units, which were victorious in the Siege of Los Angeles, and after the arrival of the United States Army, fought in the Battle of San Pasqual and the Battle of Domínguez Rancho. But the Californios were defeated in subsequent encounters, the battles of Río San Gabriel and La Mesa. The southern Californios formally surrendered with the signing of the Treaty of Cahuenga on January 13, 1847. After twenty-seven years as part of independent Mexico, California was ceded to the United States in 1848 with the signing of the Treaty of Guadalupe Hidalgo. The United States paid Mexico $15 million for the lands ceded.


title: A Bad Moms Christmas

text: A Bad Moms Christmas is a 2017 American Christmas comedy film written and directed by Jon Lucas and Scott Moore. It is a sequel to the 2016 film "Bad Moms". The plot follows the three moms from the first film (Mila Kunis, Kristen Bell, and Kathryn Hahn) dealing with their own mothers (Christine Baranski, Cheryl Hines, and Susan Sarandon) visiting during the Christmas holiday.


title: A Bad Moms Christmas

text: The film was released in the United States on November 1, 2017 and grossed over $130 million. It received mixed reviews, with criticism aimed at the thin story and raunchiness. In April 2019, it was announced that a sequel was in development.


title: A Bad Moms Christmas

text: Amy is now in a happy relationship with Jessie and wants a simple Christmas. However, her overly critical mother, Ruth, derails her plans, texting her that she is coming for the holidays. Meanwhile, Kiki is still overworked with her four kids but now her husband Kent is much more helpful. Kiki is surprised when her mother Sandy shows up earlier than expected and for three weeks, overwhelming her. Carla has her own issues as her mother, Isis, has arrived unexpectedly for the first time in years; despite Carla being happy to see Isis, she's well aware that she expects something out of it.


title: A Bad Moms Christmas

text: Amy, Kiki and Carla go to the mall and commiserate over the holidays. Complaining about the holiday pressure, they make a pact to "take Christmas back". Ruth tries to create a spectacle out of Christmas, rather than keeping it simple like Amy wants. Trying to tamp down those plans, Amy takes the family to Sky Zone to meet up with Kiki and Carla and their families. The grandmothers finally meet and chat.


title: A Bad Moms Christmas

text: At work, Carla meets erotic dancer Ty, who is in town competing in a Sexy Santa competition. He asks her to be his date, which she accepts enthusiastically. Kiki continues to have issues with her mother's overbearingness, so brings Sandy to Dr. Karl, to discuss it, end up having a communication breakdown; Kiki scolds her and Sandy leaves the session.


title: A Bad Moms Christmas

text: Amy and Kiki join Carla, attending the Sexy Santa show. Everyone is impressed with Ty's dancing. To everyone's surprise, Isis gets up on the bar and starts dancing with him. Carla runs up to get Ty back, leading to a fight. When Carla brings Isis home, she asks for money for a new investment; although Carla knows she's just going to gamble it away and then disappear as always, she loans her the money.


title: A Bad Moms Christmas

text: On Christmas Eve, Sandy tells Kiki she bought the house next door to live closer to her. Finally, Kiki lashes out, telling her she can't as she needs some space. Sandy leaves the room crying. At the same time, Amy gets angry with Ruth when she discovers she has invited strangers to her home for an elaborate Christmas party, exactly what Amy told her not to do. Realizing Ruth is only going through with this to make herself relevant rather than be there for her grandkids, Amy and Ruth then get into a fight and accidentally knock down a Christmas Tree, ruining the house. Enraged, Amy yells at Ruth to get out of her life forever. Her kids, Jane and Dylan, witness this outburst and, fearing they'll be next, become upset with Amy. Meanwhile, Carla finds a goodbye note from Isis.


title: A Bad Moms Christmas

text: Ruth goes to church for Midnight Mass, joined by Sandy and Isis. They criticize each other for their efforts as mothers, pointing out each other's flaws. Amy's father Hank talks to her about her horrible fight with her mom, where he reveals that Ruth, while difficult to deal with at times, is actually incredibly insecure and has always worried whether or not she was doing a good job as a mother, but has good intentions and loves Amy unconditionally.


title: A Bad Moms Christmas

text: Amy goes to the church where Ruth is to repair their relationship. They apologize, confessing how much they genuinely love each other. Ruth tells Amy that she is a wonderful mother. They embrace tightly. As the clock strikes midnight, Amy realizes that she needs her mother to help her fix Christmas, so they rush home to decorate the house properly.


title: A Bad Moms Christmas

text: On Christmas morning, Jane and Dylan come downstairs to see that Ruth has returned, the relationship has been repaired and the house looks wonderful. Kiki makes up with Sandy, who tells her she put the neighboring house on the market and admits that she has always felt lonely on Christmas since Kiki's father died. Carla is then visited by Isis, who is serious about turning her life around and has a new job at Sky Zone, though she confused as to how she passed the drug test.


title: A Bad Moms Christmas

text: All the families get together for an unorthodox Christmas dinner. Amy, Kiki, and Carla applaud each other for doing what they set out to do; Ty, who has legitimately fallen in love with Carla, tracks her to Amy's house to start a relationship with her; Ruth, Sandy and Isis announce that they have become friends and are now planning to take a trip to Las Vegas to see Wayne Newton (something Kiki had demanded Sandy do).


title: A Bad Moms Christmas

text: In December 2016, it was announced that "A Bad Moms Christmas" would be released on November 3, 2017, and that it would be Christmas-themed, with Bell, Hahn, and Kunis returning to reprise their roles. The release date was subsequently moved up two days to November 1, 2017. In April 2017, Justin Hartley joined the cast of the film, and in May 2017, Susan Sarandon, Christine Baranski, and Cheryl Hines joined as the mothers' mothers, alongside Wanda Sykes and Jay Hernandez reprising their roles from the first film.


title: A Bad Moms Christmas

text: "A Bad Moms Christmas" was released on Wednesday, November 1, 2017. It was originally scheduled for November 3, 2017, but was brought forward two days to avoid direct competition with "".


title: A Bad Moms Christmas

text: The film was released by Universal Pictures Home Entertainment on DVD and Blu-ray on February 6, 2018, in the United States and Canada.


title: A Bad Moms Christmas

text: "A Bad Moms Christmas" grossed $72.1 million in the United States and Canada, and $58.5 million in other territories, for a worldwide total of $130.6 million, against a production budget of $28 million.


title: A Bad Moms Christmas

text: In North America, the film was projected to gross around $25 million from 3,615 theaters in its first five days (including $17 million over the weekend). It took in $2.7 million on its first day, and $17 million over the weekend, for a five-day total of $21.6 million, finishing second at the box office behind "".


title: A Bad Moms Christmas

text: On review aggregator Rotten Tomatoes, the film holds an approval rating of based on reviews with an average rating of . The website's critical consensus reads, "Featuring twice the moms but roughly half the laughs, "A Bad Moms Christmas" is a slapdash holiday sequel that falls short of the original with a disappointing dearth of good cheer." On Metacritic, which assigns a normalized rating to reviews, the film has a weighted average score of 42 out of 100, based on 30 critics, indicating "mixed or average reviews". Audiences polled by CinemaScore gave the film an average grade of "B" on an A+ to F scale, down from the "A" earned by the first film, while PostTrak reported filmgoers gave it a "very low" 68% overall positive score.


title: A Bad Moms Christmas

text: Owen Gleiberman of "Variety" gave the film a mixed review, writing, ""A Bad Moms Christmas" should appeal to the same—dare I say it?—demo that "Bad Moms" did, even though it's not nearly as wild a comedy. It has one halfway original idea, which is that when you're a mom yourself, the ability of your own mom to drive you nuts is heightened to the third power, because you're competing on levels that are almost primal." Pete Hammond of "Deadline Hollywood" gave the film a positive review, calling it a "good time movie" and writing: "...it goes way over the top, but I have to confess I laughed—a lot—and that's obviously the point even if this is not critic's fodder or meant to be. Subtle this is not, but "A Bad Moms Christmas" is the perfect tonic to lift your spirits and forget your troubles in these dark times."


title: A Bad Moms Christmas

text: In April 2019 during CinemaCon, it was announced that a sequel titled "Bad Moms' Moms" is in development. Sarandon, Baranski, and Hines will reprise their roles. In June 2021, it was reported that "Bad Moms' Moms" had been postponed due to the COVID-19 pandemic.


title: SAE J1772

text: SAE J1772, also known as a J plug or Type 1 connector after its international standard, IEC 62196 Type 1, is a North American standard for electrical connectors for electric vehicles maintained by SAE International under the formal title "SAE Surface Vehicle Recommended Practice J1772, SAE Electric Vehicle Conductive Charge Coupler".


title: SAE J1772

text: The SAE maintains the general physical, electrical, communication protocol, and performance requirements for the electric vehicle conductive charge system and coupler. The intent is to define a common electric vehicle conductive charging system architecture including operational requirements and the functional and dimensional requirements for the vehicle inlet and mating connector.


title: SAE J1772

text: The J1772 5-pin standard supports a wide range of single-phase (1φ) alternating current (AC) charging rates. They range from portable devices that can connect to a household NEMA 5-15 outlet that can deliver 1.44 kW (12 amps @ 120 volts) to hardwired equipment that can deliver up to 19.2 kW (80 amps @ 240 volts). These connectors are sometimes informally referred to as chargers, but they are "electric vehicle supply equipment" (EVSE), since they only supply AC power to the vehicle's on-board charger, which then converts it to the direct current (DC) needed to recharge the battery.


title: SAE J1772

text: The Combined Charging System (CCS) Combo 1 connector builds on the standard, adding two additional pins for DC fast charging up to 350 kW.


title: SAE J1772

text: The main stimulus for the development of SAE J1772 came from the California Air Resources Board (CARB). Early electric vehicles like the General Motors EV1 and Toyota RAV4 EV used Magne Charge (SAE J1773), an inductive system. CARB rejected the inductive technology in favor of conductive coupling to supply electricity for recharging. In June 2001, CARB adopted the SAE J1772-2001 standard as the charging interface for electric vehicles in California. This early version of the connector was made by Avcon and featured a rectangular connector capable of delivering up to 6.6 kW of electrical power. The California regulations mandated the usage of SAE J1772-2001 beginning with the 2006 model year.


title: SAE J1772

text: CARB would later ask for higher current delivery than the 6.6 kW that the 2001 J1772 (Avcon) standard supported. This process led to the proposal of a new round connector design by Yazaki which allowed for an increased power delivery of up to 19.2 kW delivered via single phase 120–240 V AC at up to 80 amps. In 2008, CARB published a new standard that mandated the usage of the new connector beginning with the 2010 model year; this was approved in 2012.


title: SAE J1772

text: The Yazaki plug that was built to the new SAE J1772 plug standard successfully completed certification at UL. The standard specification was subsequently voted upon by the SAE committee in July 2009. On January 14, 2010, the SAE J1772 REV 2009 was adopted by the SAE Motor Vehicle Council. The companies participating in or supporting the revised 2009 standard include smart, Chrysler, GM, Ford, Toyota, Honda, Nissan, Rivian, and Tesla.


title: SAE J1772

text: The SAE J1772-2009 connector specification was subsequently added to the international IEC 62196-2 standard (“Part 2: Dimensional compatibility and interchangeability requirements for a.c. pin and contact-tube accessories”) with voting on the final specification slated to close in May 2011. The SAE J1772 connector is considered a “Type 1” implementation providing a single phase coupler.


title: SAE J1772

text: The SAE J1772-2009 was adopted by electric vehicle manufacturers in the Chevrolet Volt and the Nissan Leaf. The connector became standard equipment in the U.S. market due to the availability of charging stations supporting it in the nation's electric vehicle network (helped by funding such as the ChargePoint America program drawing grants from the American Recovery and Reinvestment Act).


title: SAE J1772

text: The European versions were equipped with a SAE J1772-2009 inlet as well until the automotive industry settled on the IEC Type 2 “Mennekes” connector as the standard inletsince all IEC connectors use the same SAE J1772 signaling protocol the car manufacturers are selling cars with either a SAE J1772-2009 inlet or an IEC Type 2 inlet depending on the regional market. There are also (passive) adapters available that can convert J1772-2009 to IEC Type 2 and vice versa. The only difference is that most European versions have an on-board charger that can take advantage of three-phase electric power with higher voltage and current limits even for the same basic electric vehicle model (such as Chevrolet Volt / Opel Ampera).


title: SAE J1772

text: In 2011, SAE developed a J1772/CCS "Combo Coupler" variant of the J1772-2009 connector in order to also support the Combined Charging System standard for direct current (DC) fast charging, which includes the standard 5-pin J1772 connector along with an additional two larger pins to support fast DC charging. "Combo 1" accommodates charging at 200–920 volts DC and up to 350 kW. The combination coupler will also use power-line communication technology to communicate between the vehicle, off-board charger, and smart grid. Seven car makers (Audi, BMW, Daimler, Ford, General Motors, Hyundai, Porsche, Volvo, and Volkswagen) agreed in late 2011 to introduce the Combined Charging System in mid-2012. The first vehicles using the SAE Combo plug were the BMW i3 released in late 2013, and the Chevrolet Spark EV released in 2014.


title: SAE J1772

text: In Europe, the combo coupler is based on the Type 2 (VDE) AC charging connector (Combo 2) maintaining full compatibility with the SAE specification for DC charging and the HomePlug Green PHY PLC protocol. In 2019 Tesla introduced the Model 3 with a CCS Combo 2 plug in Europe, but has not introduced models with CCS in the US. With the introduction of the Model 3 in Europe, Tesla added CCS charging cables to V2 Superchargers (supporting both CCS Combo 2 and Tesla DC Type 2). European V3 Tesla Superchargers include only a CCS charging cable.


title: SAE J1772

text: The J1772-2009 connector is designed for single phase alternating current electrical systems with 120 V or 240 V such as those used in North America and Japan. The round diameter connector is keyed and has five pins:


title: SAE J1772

text: The connector is designed to withstand 10,000 mating cycles (a connection and a disconnection) and exposure to the elements. With 1 mating cycle per day, the connector's lifespan should exceed 27 years.


title: SAE J1772

text: The SAE J1772 or Type 1 plug is locked into the car with a hook that is manually operated, mostly by pressing a button with the thumb, which interrupts power. This allows anybody to stop charging and even theft of the cable. To prevent this, the European IEC 62196 Type 2 connector has openings on the side for automatic locking and release, operated by the car owner via remote control. If the car locks or releases its plug, the charger will follow suit according to the PP signal.


title: SAE J1772

text: The SAE J1772-2017 standard defines four levels of charging: AC Level 1, AC Level 2, DC Level 1, and DC Level 2. Earlier released revisions of J1772 also listed a never-implemented AC Level 3, which was moved to an appendix.


title: SAE J1772

text: For example, the 2020 Chevrolet Bolt has a 66-kWh lithium-ion battery and a 7.2-kW onboard charging module (OBCM); with an EPA range of and energy efficiency of , it can use its portable charge cord to charge at AC Level 1 (120V, 12A) to get up to of range per hour or go off an AC Level 2 charging unit (240V, 32A) to get up to of range per hour. Using an optional DC fast charging (DCFC) port, this model can also charge at up to 55kW to get up to of range per half hour.


title: SAE J1772

text: Some EVs have extended J1772 to allow 120V charging at greater than 16 amps. This is useful, for example, at RV parks where TT-30 ("Travel Trailer" - 120V, 30A) receptacles are common. These allow charging at up to 24 amps. However this level of 120V charging has not been codified into J1772.


title: SAE J1772

text: Another extension, notably supported by Tesla, is Level 2 charging at 277V. Like 208V, 277V is commonly found in North American commercial three-phase circuits.


title: SAE J1772

text: The J1772 standard includes several levels of shock protection, ensuring the safety of charging even in wet conditions. Physically, the connection pins are isolated on the interior of the connector when mated, ensuring no physical access to those pins. When not mated, J1772 connectors have no power at the pins; they are not energized until commanded by the vehicle.


title: SAE J1772

text: The proximity detection pin is connected to a switch in the connector release button. Pressing the release button causes the vehicle to stop drawing current. As the connector is removed, the shorter control pilot pin disconnects first, causing the EVSE to drop power to the plug. This also ensures that the power pins will not be disconnected under load, causing arcs and shortening their life. The ground pin is longer than the other pins, so it breaks last.


title: SAE J1772

text: The technical specification was described first in the 2001 version of SAE J1772 and subsequently the IEC 61851-1 and IEC TS 62763:2013. The charging station puts 12 V on the Control Pilot (CP) and the Proximity Pilot (AKA Plug Present: PP) measuring the voltage differences. This protocol does not require integrated circuits, which would be required for other charging protocols, making the SAE J1772 robust and operable through a temperature range of −40 °C to +85 °C.


title: SAE J1772

text: Control Pilot (Mode): The charging station sends a 1 kHz square wave on the control pilot that is connected back to the protective earth on the vehicle side by means of a resistor and a diode (voltage range ±12.0±0.4 V). The live wires of public charging stations are always dead if the CP-PE (Protective Earth) circuit is open, although the standard allows a charging current as in Mode 1 (maximum 16 A). If the circuit is closed, the charging station can also verify that the protective earth is functional. The vehicle can request a certain charging function by setting the resistance between the CP and PE pins; 2.7 kΩ announces a Mode 3 compatible vehicle ("vehicle detected") which does not require charging. 880 Ω says the vehicle is "ready" to be charged, and 240 Ω requests "with ventilation" charging, in which case the charging stations supplies charging power is only if the area is ventilated (i.e., outdoors).


title: SAE J1772

text: The Control Pilot line circuitry examples in SAE J1772:2001 show that the current loop CP-PE is connected permanently on the vehicle side via a 2.74 kΩ resistor, making for a voltage drop from +12 V to +9 V when a cable is hooked up to the charging station, which activates the wave generator. The charging is activated by the vehicle by adding parallel 1.3 kΩ resistor resulting in a voltage drop to +6 V or by adding a parallel 270 Ω resistor for a required ventilation resulting in a voltage drop to +3 V. Hence the charging station can react by only checking the voltage range present on the CP-PE loop. Note that the diode will only make for a voltage drop in the positive range; any negative voltage on the CP-PE loop is blocked by D1 in the vehicle, any significant current that does flow in the CP-PE loop during the negative period will shut off the current as being considered a fatal error (like touching the pins).


title: SAE J1772

text: For IEC62196-2 male plugs the Control Pilot pin is made shorter to prevent untethered cables being used as "extension leads", This prevents the use of downstream cables that may have a lower current capability being connected to a cable of a higher current rating.


title: SAE J1772

text: Control Pilot (Current limit): The charging station can use the wave signal to describe the maximum current that is available via the charging station with the help of pulse-width modulation: a 16% PWM is a 10 A maximum, a 25% PWM is a 16 A maximum, a 50% PWM is a 32 A maximum and a 90% PWM flags a fast charge option.


title: SAE J1772

text: The PWM duty cycle of the 1 kHz CP signal indicates the maximum allowed mains current. According to the SAE it includes socket outlet, cable and vehicle inlet. In the US, the definition of the "ampacity" (ampere capacity, or current capacity) is split for continuous and short term operation. The SAE defines the ampacity value to be derived by a formula based on the 1 ms full cycle (of the 1 kHz signal) with the maximum continuous ampere rating being 0.6 A per 10 µs up to 850 µs (with the lowest 100 µs × 0.6 A = 6 A). Above 850 µs, the formula requires subtraction of 640 µs and multiplying the difference by 2.5. For example (960 µs − 640 µs) × 2.5 A = 80 A.


title: SAE J1772

text: The proximity pin, PP (also known as "plug present"), as shown in the SAE J1772 example pinout, describes the switch, S3, as being mechanically linked to the connector latch release actuator. During charging, the EVSE side connects the PP-PE loop via S3 and a 150 Ω R6; when opening the release actuator a 330 Ω R7 is added in the PP-PE loop on the EVSE side which gives a voltage shift on the line to allow the electric vehicle to initiate a controlled shut off prior to actual disconnection of the charge power pins. However, many low-power adapter cables do not offer that locking actuator state detection on the PP pin.


title: SAE J1772

text: Under IEC 62196 the Proximity Pin is also used to indicate the cable capacity – this is relevant for non-tethered EVSEs.


title: SAE J1772

text: The resistor is coded to the maximum current capability of the cable assembly. The EVSE interrupts the current supply if the current capability of the cable is exceeded as detected by the measurement of the Rc (shown as R5 in the J1772 signaling circuit above), as defined by the values for the recommended interpretation range.


title: SAE J1772

text: In an updated standard due in 2012, SAE proposes to use power line communication, specifically IEEE 1901, between the vehicle, off-board charging station, and the smart grid, without requiring an additional pin; SAE and the IEEE Standards Association are sharing their draft standards related to the smart grid and vehicle electrification.


title: SAE J1772

text: P1901 communication is compatible with other 802.x standards via the IEEE 1905 standard, allowing arbitrary IP-based communications with the vehicle, meter or distributor, and the building where chargers are located. P1905 includes wireless communications. In at least one implementation, communication between the off-board DC EVSE and PEV occurs on the pilot wire of the SAE J1772 connector via HomePlug Green PHY power line communication (PLC).


title: SAE J1772

text: A competing proposal known as the Mennekes connector initiated by RWE and Daimler was standardized in 2011's IEC 62196 as its Type 2 connector. It has been widely adopted as the European Union's standard single and three phase coupler. The connector adopted the same protocols for the pilot pin as J1772's J-Plug. The IEC specification allows for up to 63 A and 43.6 kW. In 2018, the SAE J3068 committee released an enhancement to the EU connector tailored for the North American industrial market allowing up to 160 A / 166 kW on 3φ power.


title: SAE J1772

text: The same IEC 62196-2 standard also specified a pair of Type 3 connector from Scame Global providing a single and three phase coupler with shutters. After a 2016 approval by the IEC for a small modification to the Mennekes connector optionally allowing shutters, Type 3 has been deprecated.


title: SAE J1772

text: Tokyo Electric Power Company has developed a specification solely for automotive high-voltage DC fast charging using the JARI DC connector, and formed the CHAdeMO ("charge de move", equivalent to "charge for moving") association with Japanese automakers Mitsubishi, Nissan and Subaru to promote it.


title: Phorusrhacidae

text: Phorusrhacids, colloquially known as terror birds, are an extinct clade of large carnivorous flightless birds that were one of the largest species of apex predators in South America during the Cenozoic era; their conventionally accepted temporal range covers from 62 to 0.1 million years (Ma) ago.


title: Phorusrhacidae

text: They ranged in height from . Their closest modern-day relatives are believed to be the seriemas. "Titanis walleri", one of the larger species, is known from Texas and Florida in North America. This makes the phorusrhacids the only known large South American predator to migrate north in the Great American Interchange that followed the formation of the Isthmus of Panama land bridge (the main pulse of the interchange began about 2.6 Ma ago; "Titanis" at 5 Ma was an early northward migrant).


title: Phorusrhacidae

text: It was once believed that "T. walleri" became extinct in North America around the time of the arrival of humans, but subsequent datings of "Titanis" fossils provided no evidence for their survival after 1.8 Ma. However, reports from Uruguay of new findings of a relatively small form ("Psilopterus)" dating to 18,000 and 96,000 years ago would imply that phorusrhacids survived there until very recently (i.e., until the late Pleistocene); the initial report of such a recent date has been questioned.


title: Phorusrhacidae

text: Phorusrhacids may have even made their way into Africa; the genus "Lavocatavis" was discovered in Algeria, but its status as a true phorusrhacid is questioned. A possible European form, "Eleutherornis", has also been identified, suggesting that this group had a wider geographical range in the Paleogene.


title: Phorusrhacidae

text: The closely related bathornithids occupied a similar ecological niche in North America across the Eocene to Early Miocene; some, like "Paracrax", were similar in size to the largest phorusrhacids. At least one analysis recovers "Bathornis" as sister taxa to phorusrhacids, on the basis of shared features in the jaws and coracoid, though this has been seriously contested, as these might have evolved independently for the same carnivorous, flightless lifestyle.


title: Phorusrhacidae

text: The neck can be divided into three main regions. In the higher regions of the neck, the phorusrhacid has bifurcate neural spines (BNS), while it has high neural spines in its lower regions. This suggests that the phorusrhacid had a highly flexible and developed neck allowing it to carry its heavy head and strike with terrifying speed and power. Although the phorusrhacid externally looks like it has a short neck, its flexible skeletal neck structure proves that it could expand farther beyond the expected reach and intimidate its prey using its height, allowing it to strike more easily. Once stretched out into its full length in preparation for a downward strike, its developed neck muscles and heavy head could produce enough momentum and power to cause fatal damage to the terror bird's prey.


title: Phorusrhacidae

text: "Kelenken guillermoi", from the Langhian stage of the Miocene epoch, some 15 million years ago, discovered in the Collón Curá Formation in Patagonia in 2006, represents the largest bird skull yet found. The fossil has been described as being a , nearly intact skull. The beak is roughly long and curves in a hook shape that resembles an eagle's beak. Most species described as phorusrhacid birds were smaller, tall, but the new fossil belongs to a bird that probably stood about tall. Scientists theorize that the large terror birds were extremely nimble and quick runners, able to reach speeds of . Examination of phorusrhacid habitats also indicates that phorusrhacids may have presented intense competition to predatory metatherian sparassodonts such as borhyaenids and thylacosmilids, causing the mammalian predators to choose forested habitats to avoid the more successful and aggressive avian predators on the open plains.


title: Phorusrhacidae

text: The feet of the phorusrhacids had four toes, the first of which, known as the hallux, was reduced and did not touch the ground, while the others, corresponding to the second, third and fourth toes, were kept on the ground. Analysis of the resistance of the toes based on biomechanical models of curved beams, in particular of the second toe and its nail claw, indicate that its design was relatively uniform in various species and that said claw would be relatively curved and large, which implies the need to keep it elevated to avoid wear or breakage due to contact with the ground, which would be achieved with a well-developed extensor tubercle and soft tissue pads on the fingers. The second toe, which was shorter and had fewer phalanges, also had more resistance and would make it easier to hold the claw off the ground and retain prey, a compromise with its predatory function and movement on the run, as occurs with modern seriemas, although to a lesser degree of specialization than dromaeosaurid dinosaurs.


title: Phorusrhacidae

text: Most phorusrhacids were very fast runners. All members possessed a large, sharp beak, a powerful neck and sharp talons. However, even with these attributes, the phorusrhacids are often assumed to have preyed on relatively small animals (about the size of a rabbit) that could be dispatched with a minimum of struggle. This is because with the phorusrhacids' beak proportions, the jaw could not generate a great deal of bite force with which to kill the prey. This is disputable as many big-game hunting predators such as "Smilodon", great white sharks and "Allosaurus" have weaker bite forces and often laterally weak skulls as adaptations towards, not away from, killing large prey, relying instead on the presence of a cutting edge, a wide gape made possible by the reduction of jaw musculature, and the driving force of the body or neck. Since phorusrhacids share many of the same adaptations, such as a large, laterally flattened skull with a sharp-edged beak and powerful neck musculature, it is possible that they were specialized predators of relatively large prey.


title: Phorusrhacidae

text: The bones of the beak were tightly fused together, making the beak more resilient to force from the front to back direction, thus suggesting that it could cause a great amount of harm through pecking as opposed to side-to-side head movements like shaking prey. Generally speaking, it is thought that a terror bird would use its feet to injure prey by kicking it, and to hold the prey down and dispatch by pecking at it with its large beak. Larger prey may also have been attacked by pecking and kicking, or by using the beak as a blade to strike at or slash vital organs.


title: Phorusrhacidae

text: It has been recently shown that at least some phorusrhacids like "Andalgalornis", while very fast runners in a straight line, were poor at tight turns at speed, which contradicts the idea of phorusrhacids being agile predators of small prey.


title: Phorusrhacidae

text: All phorusrhacids are thought to have been carnivorous. The strong downwards curve from the tip of this beak suggests that it ripped the flesh from the body of other animals; many extant bird species with this feature are carnivorous. CT scans performed on the skull of a phorusrhacid reveal that the species would not have been able to shake its prey side to side, but rather exert significant downward force. Florentino Ameghino claimed in a letter to Édouard Trouessart that he had specimens from Argentina of "petrified masses preserving skeletons of large rodents, Interatheriidae [small notoungulates] and even Proterotheriidae [deer-sized litopterns], with all their bones crushed and corroded, piled on with no apparent order and forming a nearly spherical mass with the skull in the center" that resembled giant owl pellets, suggesting that phorusrhacids may have swallowed their prey whole and regurgitated the indigestible parts similar to owls. However, Ameghino never formally described these specimens and they have not yet been relocated, making it difficult to determine if they are phorusrhacid pellets. Fossilized pellets from northwestern Argentina have also been suggested to pertain to small phorusrhacids like "Procariama".


title: Phorusrhacidae

text: During the Miocene and early Pliocene epochs, there was an increase in the phorusrhacid population size in South America, suggesting that, in that time frame, the various species flourished as predators in the savanna environment.


title: Phorusrhacidae

text: With the emergence of the Isthmus of Panama 2.7 million years ago, carnivorous dogs, bears, and cats from North America were able to cross into South America, increasing competition. (They had been preceded by procyonids as early as 7.3 million years ago.) The population of phorusrhacids declined thereafter according to older hypotheses, suggesting that competition with newly arrived predators was a major contributor to their extinction. Similar ideas have been considered for sparassodonts and for South America's terrestrial sebecid crocodilians.


title: Phorusrhacidae

text: However, the role of competitive displacement in South American predator lineages has been questioned by some researchers. The timing of turnover events and the decline of South American predators do not correlate well with the arrival of large carnivores like canids or sabretooths (although they do correlate well with the earlier-arriving procyonids, which evolved to large body size in South America, but these were omnivorous), with native South American predator lineages (including most phorusrhacids and all sparassodonts and sebecids) dying out well before the arrival of most larger placental carnivores. Bathornithids, which were similar in ecology and are likely close relatives of phorusrhacids, existed entirely within North America during part of the Cenozoic and competed successfully for a time with large carnivorans such as nimravids, before becoming extinct in the Early Miocene, about 20 million years ago. The phorusrhacid "Titanis" expanded northward into a southern North America during the Interchange and coexisted for several million years with large canids and big cats like "Xenosmilus", before its extinction about 1.8 million years ago.


title: Phorusrhacidae

text: There were some suggestions that phorusrhacids, like the majority of Pleistocene megafauna, were killed off by human activity such as hunting or habitat change. This idea is no longer considered valid, as improved dating on "Titanis" specimens show that the last phorusrhacids went extinct over one million years before humans arrived. However, several fossil finds of smaller forms have been described from the late Pleistocene of South America. "Psilopterus" may have been present until 96,040 ± 6,300 years ago. Another unidentified smaller type has also been dated to the late Pleistocene, perhaps 18,000 years ago. These finds, if accepted, extend the existence of the smaller members of this group of avian predators considerably.


title: Phorusrhacidae

text: In the past, these birds were thought to have high beaks, round orbits, and vaulted braincases though there was never enough empirical evidence to support this. However, new fossils have been discovered in Comallo, Argentina. These skulls reveal that the terror bird has a triangular dorsal view, a rostrum that is hooked and more than half the length of the actual skull, and a more compact caudal portion. The external nares and antorbital fenestras (areas found in the nose) were found to be more square than triangular. These all contribute to a skull that is more rectangular in view rather than triangular. The structure of the fossils also suggest that these birds may have been swifter than originally thought.


title: Phorusrhacidae

text: A skull from a smaller subspecies of this bird was also found recently. With this fossil, it was found that the internal structure of the beak is hollow and reinforced with thin-walled trabeculae. There is also an absence of both zona flexoria palatina and zona flexoria arcus jugalis, which are key features that relate to the evolution of cranial akinesis. The discovery of this skull allows for the establishment of primary osteological homologies, which are useful in comparative anatomy, functional morphology, and phylogenetic studies.


title: Phorusrhacidae

text: The etymology of the name Phorusrhacidae is based on the type genus "Phorusrhacos". When first described by Florentino Ameghino in 1887, the etymology of "Phorusrhacos" was not given. Current thinking is that the name is derived from a combination of the Greek words "phoros", which means "bearer" or "bearing", and "rhakos", which translates to "wrinkles", "scars" or "rents". Researchers have compared Phorusrhacidae with the living families of Cariamidae and Sagittariidae, but their differences in body mass are too drastic and, thus, one cannot overly depend on these living families for answers.


title: Phorusrhacidae

text: Following the revision by Alvarenga and Höfling (2003), there are now 5 subfamilies, containing 14 genera and 18 species: These species were the product of adaptive radiation.


title: Phorusrhacidae

text: Alvarenga and Höfling did not include the Ameghinornithidae from Europe in the phorusrhacoids; these have meanwhile turned out to be more basal members of Cariamae. Though traditionally considered as members of the Gruiformes, based on both morphological and genetic studies (the latter being based on the seriema) Cariamiformes may belong to a separate group of birds, Australaves, and their closest living relatives, according to nuclear sequence studies, are a clade consisting of Falconidae, Psittaciformes and Passeriformes.


title: Tariff

text: A tariff is a tax imposed by the government of a country or by a supranational union on imports or exports of goods. Besides being a source of revenue for the government, import duties can also be a form of regulation of foreign trade and policy that taxes foreign products to encourage or safeguard domestic industry. "Protective tariffs" are among the most widely used instruments of protectionism, along with import quotas and export quotas and other non-tariff barriers to trade.


title: Tariff

text: Tariffs can be fixed (a constant sum per unit of imported goods or a percentage of the price) or variable (the amount varies according to the price). Taxing imports means people are less likely to buy them as they become more expensive. The intention is that they buy local products instead, boosting their country's economy. Tariffs therefore provide an incentive to develop production and replace imports with domestic products. Tariffs are meant to reduce pressure from foreign competition and reduce the trade deficit. They have historically been justified as a means to protect infant industries and to allow import substitution industrialization. Tariffs may also be used to rectify artificially low prices for certain imported goods, due to 'dumping', export subsidies or currency manipulation.


title: Tariff

text: There is near unanimous consensus among economists that tariffs have a negative effect on economic growth and economic welfare, while free trade and the reduction of trade barriers has a positive effect on economic growth. Although trade liberalization can sometimes result in large and unequally distributed losses and gains, and can, in the short run, cause significant economic dislocation of workers in import-competing sectors, free trade has advantages of lowering costs of goods and services for both producers and consumers.


title: Tariff

text: The English term "tariff" derives from the which is itself a descendant of the which derives from . This term was introduced to the Latin-speaking world through contact with the Turks and derives from the . This Turkish term is a loanword of the . The Persian term derives from which is the verbal noun of .


title: Tariff

text: In the city state of Athens, the port of Piraeus enforced a system of levies to raise taxes for the Athenian government. Grain was a key commodity that was imported through the port, and Piraeus was one of the main ports in the east Mediterranean. A levy of two percent was placed on goods arriving in the market through the docks of Piraeus. Despite the Peloponnesian War preceding year 399 BC, Piraeus had documented a tax income of 1,800 in harbor dues. The Athenian government also placed restrictions on the lending of money and transport of grain to only be allowed through the port of Piraeus.


title: Tariff

text: In the 14th century, Edward III (1312–1377) took interventionist measures, such as banning the import of woollen cloth in an attempt to develop local woollen cloth manufacturing. Beginning in 1489, Henry VII took actions such as increasing export duties on raw wool. The Tudor monarchs, especially Henry VIII and Elizabeth I, used protectionism, subsidies, distribution of monopoly rights, government-sponsored industrial espionage and other means of government intervention to develop the wool industry, leading to England became the largest wool-producing nation in the world.


title: Tariff

text: A protectionist turning point in British economic policy came in 1721, when policies to promote manufacturing industries were introduced by Robert Walpole. These included increased tariffs on imported foreign manufactured goods, and export subsidies. These policies were similar to those used by countries such as Japan, Korea and Taiwan after the Second World War. In addition, in its colonies, Great Britain imposed a ban on advanced manufacturing activities that it did not want to see developed. Britain also banned exports from its colonies that competed with its own products at home and abroad, forcing the colonies to leave the most profitable industries in Britain's hands.


title: Tariff

text: In 1800, Britain, with about 10% of Europe's population, supplied 29% of all pig iron produced in Europe, a proportion that had risen to 45% by 1830. Per capita industrial production was even higher: in 1830 it was 250% higher than in the rest of Europe, up from 110% in 1800.


title: Tariff

text: Protectionist policies of industrial promotion continued until the mid-19th century. At the beginning of that century, the average tariff on British manufactured goods was about 50%, the highest of all major European countries. Thus, according to economic historian Paul Bairoch, Britain's technological advance was achieved "behind high and enduring tariff barriers". In 1846, the country's per capita rate of industrialization was more than twice that of its closest competitors. Even after adopting free trade for most goods, Britain continued to closely regulate trade in strategic capital goods, such as machinery for the mass production of textiles.


title: Tariff

text: Free trade in Britain began in earnest with the repeal of the Corn Laws in 1846, which was equivalent to free trade in grain. The Corn Acts had been passed in 1815 to restrict wheat imports and to guarantee the incomes of British farmers; their repeal devastated Britain's old rural economy, but began to mitigate the effects of the Great Famine in Ireland. Tariffs on many manufactured goods were also abolished. But while liberalism was progressing in Britain, protectionism continued on the European mainland and in the United States.


title: Tariff

text: On June 15, 1903, the Secretary of State for Foreign Affairs, Henry Petty-Fitzmaurice, 5th Marquess of Lansdowne, made a speech in the House of Lords in which he defended fiscal retaliation against countries that applied high tariffs and whose governments subsidized products sold in Britain (known as "premium products", later called "dumping"). The retaliation was to take the form of threats to impose duties in response to goods from that country. Liberal unionists had split from the liberals, who advocated free trade, and this speech marked a turning point in the group's slide toward protectionism. Lansdowne argued that the threat of retaliatory tariffs was similar to gaining respect in a room of gunmen by pointing a big gun (his exact words were "a gun a little bigger than everyone else's"). The "Big Revolver" became a slogan of the time, often used in speeches and cartoons.


title: Tariff

text: In response to the Great Depression, Britain finally abandoned free trade in 1932 and reintroduced tariffs on a large scale, noticing that it had lost its production capacity to protectionist countries like the United States and Weimar Germany.


title: Tariff

text: Before the new Constitution took effect in 1788, the Congress could not levy taxesit sold land or begged money from the states. The new national government needed revenue and decided to depend upon a tax on imports with the Tariff of 1789. The policy of the U.S. before 1860 was low tariffs "for revenue only" (since duties continued to fund the national government). A high tariff was attempted in 1828 but the South denounced it as a "Tariff of Abominations" and it almost caused a rebellion in South Carolina until it was lowered.


title: Tariff

text: Between 1816 and the end of the Second World War, the United States had one of the highest average tariff rates on manufactured imports in the world. According to Paul Bairoch, the United States was "the homeland and bastion of modern protectionism"during this period


title: Tariff

text: Many American intellectuals and politicians during the country's catching-up period felt that the free trade theory advocated by British classical economists was not suited to their country. They argued that the country should develop manufacturing industries and use government protection and subsidies for this purpose, as Britain had done before them. Many of the great American economists of the time, until the last quarter of the 19th century, were strong advocates of industrial protection: Daniel Raymond who influenced Friedrich List, Mathew Carey and his son Henry, who was one of Lincoln's economic advisers. The intellectual leader of this movement was Alexander Hamilton, the first Secretary of the Treasury of the United States (1789-1795). Thus, it was against David Ricardo's theory of comparative advantage that the United States protected its industry. They pursued a protectionist policy from the beginning of the 19th century until the middle of the 20th century, after the Second World War.


title: Tariff

text: In Report on Manufactures, considered the first text to express modern protectionist theory, Alexander Hamilton argued that if a country wished to develop a new activity on its soil, it would have to temporarily protect it. According to him, this protection against foreign producers could take the form of import duties or, in rare cases, prohibition of imports. He called for customs barriers to allow American industrial development and to help protect infant industries, including bounties (subsidies) derived in part from those tariffs. He also believed that duties on raw materials should be generally low. Hamilton argued that despite an initial "increase of price" caused by regulations that control foreign competition, once a "domestic manufacture has attained to perfection… it invariably becomes cheaper. He believed that political independence was predicated upon economic independence. Increasing the domestic supply of manufactured goods, particularly war materials, was seen as an issue of national security. And he feared that Britain's policy towards the colonies would condemn the United States to be only producers of agricultural products and raw materials.


title: Tariff

text: Britain initially did not want to industrialize the American colonies, and implemented policies to that effect (for example, banning high value-added manufacturing activities). Under British rule, America was denied the use of tariffs to protect its new industries. This explains why, after independence, the Tariff Act of 1789 was the second bill of the Republic signed by President Washington allowing Congress to impose a fixed tariff of 5% on all imports, with a few exceptions.


title: Tariff

text: The Congress passed a tariff act (1789), imposing a 5% flat rate tariff on all imports. Between 1792 and the war with Britain in 1812, the average tariff level remained around 12.5%. In 1812 all tariffs were doubled to an average of 25% in order to cope with the increase in public expenditure due to the war. A significant shift in policy occurred in 1816, when a new law was introduced to keep the tariff level close to the wartime level—especially protected were cotton, woolen, and iron goods. The American industrial interests that had blossomed because of the tariff lobbied to keep it, and had it raised to 35 percent in 1816. The public approved, and by 1820, America's average tariff was up to 40 percent.


title: Tariff

text: In the 19th century, statesmen such as Senator Henry Clay continued Hamilton's themes within the Whig Party under the name "American System which consisted of protecting industries and developing infrastructure in explicit opposition to the "British system" of free trade. Before 1860 they were always defeated by the low-tariff Democrats.


title: Tariff

text: From 1846 to 1861, during which American tariffs were lowered but this was followed by a series of recessions and the 1857 panic, which eventually led to higher demands for tariffs than President James Buchanan, signed in 1861 (Morrill Tariff).


title: Tariff

text: During the American Civil War (1861-1865), agrarian interests in the South were opposed to any protection, while manufacturing interests in the North wanted to maintain it. The war marked the triumph of the protectionists of the industrial states of the North over the free traders of the South. Abraham Lincoln was a protectionist like Henry Clay of the Whig Party, who advocated the "American system" based on infrastructure development and protectionism. In 1847, he declared: ""Give us a protective tariff, and we will have the greatest nation on earth"". Once elected, Lincoln raised industrial tariffs and after the war, tariffs remained at or above wartime levels. High tariffs were a policy designed to encourage rapid industrialisation and protect the high American wage rates.


title: Tariff

text: The policy from 1860 to 1933 was usually high protective tariffs (apart from 1913 to 1921). After 1890, the tariff on wool did affect an important industry, but otherwise the tariffs were designed to keep American wages high. The conservative Republican tradition, typified by William McKinley was a high tariff, while the Democrats typically called for a lower tariff to help consumers but they always failed until 1913.


title: Tariff

text: In the early 1860s, Europe and the United States pursued completely different trade policies. The 1860s were a period of growing protectionism in the United States, while the European free trade phase lasted from 1860 to 1892. The tariff average rate on imports of manufactured goods was in 1875 from 40% to 50% in the United States against 9% to 12% in continental Europe at the height of free trade.


title: Tariff

text: In 1896, the GOP pledged platform pledged to "renew and emphasize our allegiance to the policy of protection, as the bulwark of American industrial independence, and the foundation of development and prosperity. This true American policy taxes foreign products and encourages home industry. It puts the burden of revenue on foreign goods; it secures the American market for the American producer. It upholds the American standard of wages for the American workingman".


title: Tariff

text: In 1913, following the electoral victory of the Democrats in 1912, there was a significant reduction in the average tariff on manufactured goods from 44% to 25%. However, the First World War rendered this bill ineffective, and new "emergency" tariff legislation was introduced in 1922, after the Republicans returned to power in 1921.


title: Tariff

text: According to economic historian Douglas Irwin, a common myth about United States trade policy is that low tariffs harmed American manufacturers in the early 19th century and then that high tariffs made the United States into a great industrial power in the late 19th century. A review by the "Economist" of Irwin's 2017 book "Clashing over Commerce: A History of US Trade Policy" notes:Political dynamics would lead people to see a link between tariffs and the economic cycle that was not there. A boom would generate enough revenue for tariffs to fall, and when the bust came pressure would build to raise them again. By the time that happened, the economy would be recovering, giving the impression that tariff cuts caused the crash and the reverse generated the recovery. Mr Irwin also methodically debunks the idea that protectionism made America a great industrial power, a notion believed by some to offer lessons for developing countries today. As its share of global manufacturing powered from 23% in 1870 to 36% in 1913, the admittedly high tariffs of the time came with a cost, estimated at around 0.5% of GDP in the mid-1870s. In some industries, they might have sped up development by a few years. But American growth during its protectionist period was more to do with its abundant resources and openness to people and ideas.


title: Tariff

text: The economist Ha-Joon Chang disagrees with the idea that the United States has developed and reached the top of the world economic hierarchy by adopting free trade. On the contrary, according to him, they have adopted an interventionist policy to promote and protect their industries through tariffs. It was their protectionist policy that would have allowed the United States to experience the fastest economic growth in the world throughout the 19th century and into the 1920s.


title: Tariff

text: Most economists hold the opinion that the Smoot-Hawley Tariff Act in the United States did not greatly worsen the Great Depression:


title: Tariff

text: Paul Krugman writes that protectionism does not lead to recessions. According to him, the decrease in imports (which can be obtained by introducing tariffs) has an expansive effect, that is, it is favorable to growth. Thus, in a trade war, since exports and imports will decrease equally, for everyone, the negative effect of a decrease in exports will be offset by the expansionary effect of a decrease in imports. Therefore, a trade war does not cause a recession. Furthermore, he points out that the Smoot-Hawley tariff did not cause the Great Depression. The decline in trade between 1929 and 1933 "was almost entirely a consequence of the Depression, not a cause. Trade barriers were a response to the Depression, partly as a consequence of deflation."


title: Tariff

text: Milton Friedman held the opinion that the tariffs of 1930 did not cause the Great Depression, instead he blamed the lack of sufficient action on the part of the Federal Reserve. Douglas A. Irwin wrote: "most economists, both liberal and conservative, doubt that Smoot–Hawley played much of a role in the subsequent contraction".


title: Tariff

text: Peter Temin, an economist at the Massachusetts Institute of Technology, explained that a tariff is an expansionary policy, like a devaluation as it diverts demand from foreign to home producers. He noted that exports were 7 percent of GNP in 1929, they fell by 1.5 percent of 1929 GNP in the next two years and the fall was offset by the increase in domestic demand from tariff. He concluded that contrary the popular argument, contractionary effect of the tariff was small.


title: Tariff

text: William Bernstein wrote: "Between 1929 and 1932, real GDP fell 17 percent worldwide, and by 26 percent in the United States, but most economic historians now believe that only a minuscule part of that huge loss of both world GDP and the United States’ GDP can be ascribed to the tariff wars. .. At the time of Smoot-Hawley's passage, trade volume accounted for only about 9 percent of world economic output. Had all international trade been eliminated, and had no domestic use for the previously exported goods been found, world GDP would have fallen by the same amount — 9 percent. Between 1930 and 1933, worldwide trade volume fell off by one-third to one-half. Depending on how the falloff is measured, this computes to 3 to 5 percent of world GDP, and these losses were partially made up by more expensive domestic goods. Thus, the damage done could not possibly have exceeded 1 or 2 percent of world GDP — nowhere near the 17 percent falloff seen during the Great Depression... The inescapable conclusion: contrary to public perception, Smoot-Hawley did not cause, or even significantly deepen, the Great Depression,"("A Splendid Exchange: How Trade Shaped the World, William Bernstein")


title: Tariff

text: Jacques Sapir explains that the crisis has other causes than protectionism. He points out that "domestic production in major industrialized countries is declining...faster than international trade is declining." If this decrease (in international trade) had been the cause of the depression that the countries have experienced, we would have seen the opposite". "Finally, the chronology of events does not correspond to the thesis of the free traders... The bulk of the contraction of trade occurred between January 1930 and July 1932, that is, before the introduction of protectionist measures, even self-sufficient, in some countries, with the exception of those applied in the United States in the summer of 1930, but with negative effects. very limited. He noted that "the credit crunch is one of the main causes of the trade crunch." "In fact, international liquidity is the cause of the trade contraction. This liquidity collapsed in 1930 (-35.7%) and 1931 (-26.7%). A study by the National Bureau of Economic Research highlights the predominant influence of currency instability (which led to the international liquidity crisis) and the sudden rise in transportation costs in the decline of trade during the 1930s .


title: Tariff

text: The Russian Federation adopted more protectionist trade measures in 2013 than any other country, making it the world leader in protectionism. It alone introduced 20% of protectionist measures worldwide and one-third of measures in the G20 countries. Russia's protectionist policies include tariff measures, import restrictions, sanitary measures, and direct subsidies to local companies. For example, the government supported several economic sectors such as agriculture, space, automotive, electronics, chemistry, and energy.


title: Tariff

text: From 2017, as part of the promotion of its "Make in India" programme to stimulate and protect domestic manufacturing industry and to combat current account deficits, India has introduced tariffs on several electronic products and "non-essential items". This concerns items imported from countries such as China and South Korea. For example, India's national solar energy programme favours domestic producers by requiring the use of Indian-made solar cells.


title: Tariff

text: Armenia, a country located in Western Asia, established its custom service in 1992 after the dissolution of the Soviet Union. When Armenia became a member of the EAEU, it was given access to the Eurasian Customs Union in 2015; this resulted in mostly tariff-free trade with other members and an increased number of import tariffs from outside of the customs union. Armenia does not currently have export taxes. In addition, it does not declare temporary imports duties and credit on government imports or pursuant to other international assistance imports. Upon joining Eurasian Economic Union in 2015, led by Russians, Armenia applied tariffs on its imports at a rate 0-10 percent. This rate has increased over the years, since in 2009 it was around three percent. Moreover, the tariffs increased significantly on agricultural products rather than on non-agricultural products.


title: Tariff

text: Armenia has committed to ultimately adopting the EAEU's uniform tariff schedule as part of its EAEU admission. Armenia will be authorized to apply customs tariffs that differ from the EAEU tariff rates until 2022, according to Decision No. 113. Some beef, pork, poultry, and dairy products; seed potatoes and peas; olives; fresh and dried fruits; some tea items; cereals, especially wheat and rice; starches, vegetable oils, margarine; some prepared food items, such as infant food; pet food; tobacco; glycerol; and gelatin are included in the list.


title: Tariff

text: Membership in the EAEU is forcing Armenia to apply stricter standardization, sanitary, and phytosanitary requirements in line with EAEU—and, by extension, Russian—standards, regulations, and practices. Armenia has had to surrender control over many aspects of its foreign trade regime in the context of EAEU membership. Tariffs have also increased, granting protection to several domestic industries. Armenia is increasingly beholden to comply with EAEU standards and regulations as post-accession transition periods have, or will soon, end. All Armenian goods circulating in the territory of the EAEU must meet EAEU requirements following the end of relevant transition periods.


title: Tariff

text: The Republic of Armenia has become a member of WTO in 2003, which resulted in the Most Favored Country(MFC) benefits from the organisation. Currently, the tariffs of 2.7% implemented in Armenia are the lowers in the entire framework. Align with the World Customs Organization (WCO), which the country is also a member of harmonized System for tariff classification, which is a method of a consistent numbering system for categorising traded goods.


title: Tariff

text: A customs duty or due is the indirect tax levied on the import or export of goods in international trade. In economics a duty is also a kind of consumption tax. A duty levied on goods being imported is referred to as an 'import duty', and one levied on exports an 'export duty'.


title: Tariff

text: Customs duty is calculated on the determination of the 'assess-able value' in case of those items for which the duty is levied . This is often the transaction value unless a customs officer determines assess-able value in accordance with the Harmonized System. For certain items like petroleum and alcohol, customs duty is realized at a specific rate applied to the volume of the import or export consignments.


title: Tariff

text: For the purpose of assessment of customs duty, products are given an identification code that has come to be known as the Harmonized System code. This code was developed by the World Customs Organization based in Brussels. A 'Harmonized System' code may be from four to ten digits. For example, 17.03 is the HS code for "molasses from the extraction or refining of sugar". However, within 17.03, the number 17.03.90 stands for "Molasses (Excluding Cane Molasses)".


title: Tariff

text: Introduction of Harmonized System codes in the 1990s has largely replaced the previous Standard International Trade Classification (SITC), though SITC remains in use for statistical purposes. In drawing up the national tariff, the revenue departments often specifies the rate of customs duty with reference to the HS code of the product. In some countries and customs unions, 6-digit HS codes are locally extended to 8 digits or 10 digits for further tariff discrimination: for example the European Union uses its 8-digit CN (Combined Nomenclature) and 10-digit TARIC codes.


title: Tariff

text: The national customs authority in each country is responsible for collecting taxes on the import into or export of goods out of the country. Normally the customs authority, operating under national law, is authorized to examine cargo in order to ascertain actual description, specification volume or quantity, so that the assessable value and the rate of duty may be correctly determined and applied.


title: Tariff

text: Evasion of customs duties takes place mainly in two ways. In one, the trader under-declares the value so that the assessable value is lower than actual. In a similar vein, a trader can evade customs duty by understatement of quantity or volume of the product of trade. A trader may also evade duty by misrepresenting traded goods, categorizing goods as items which attract lower customs duties. The evasion of customs duty may take place with or without the collaboration of customs officials.


title: Tariff

text: Many countries allow a traveller to bring goods into the country duty-free. These goods may be bought at ports and airports or sometimes within one country without attracting the usual government taxes and then brought into another country duty-free. Some countries specify 'duty-free allowances' which limit the number or value of duty-free items that one person can bring into the country. These restrictions often apply to tobacco, wine, spirits, cosmetics, gifts and souvenirs. Often foreign diplomats and UN officials are entitled to duty-free goods.


title: Tariff

text: Goods may be imported and stocked duty-free in a bonded warehouse: duty becomes payable on leaving the facility. Products may sometimes be imported into a free economic zone (or 'free port'), processed there, then re-exported without being subject to tariffs or duties. According to the 1999 Revised Kyoto Convention, a "'free zone' means a part of the territory of a contracting party where any goods introduced are generally regarded, insofar as import duties and taxes are concerned, as being outside the customs territory".


title: Tariff

text: Neoclassical economic theorists tend to view tariffs as distortions to the free market. Typical analyses find that tariffs tend to benefit domestic producers and government at the expense of consumers, and that the net welfare effects of a tariff on the importing country are negative due to domestic firms not producing more efficiently since there is a lack of external competition. Therefore, domestic consumers are affected since the price is higher due to high costs caused due to inefficient production or if firms aren't able to source cheaper material externally thus reducing the affordability of the products. Normative judgments often follow from these findings, namely that it may be disadvantageous for a country to artificially shield an industry from world markets and that it might be better to allow a collapse to take place. Opposition to all tariff aims to reduce tariffs and to avoid countries discriminating between differing countries when applying tariffs. The diagrams at right show the costs and benefits of imposing a tariff on a good in the domestic economy.


title: Tariff

text: Imposing an import tariff has the following effects, shown in the first diagram in a hypothetical domestic market for televisions:


title: Tariff

text: The overall change in welfare = Change in Consumer Surplus + Change in Producer Surplus + Change in Government Revenue = (−A−B−C−D) + A + C = −B−D. The final state after imposition of the tariff is indicated in the second diagram, with overall welfare reduced by the areas labeled "societal losses", which correspond to areas B and D in the first diagram. The losses to domestic consumers are greater than the combined benefits to domestic producers and government.


title: Tariff

text: That tariffs overall reduce welfare is not a controversial topic among economists. For example, the University of Chicago surveyed about 40 leading economists in March 2018 asking whether "Imposing new U.S. tariffs on steel and aluminum will improve Americans' welfare." About two-thirds strongly disagreed with the statement, while one third disagreed. None agreed or strongly agreed. Several commented that such tariffs would help a few Americans at the expense of many. This is consistent with the explanation provided above, which is that losses to domestic consumers outweigh gains to domestic producers and government, by the amount of deadweight losses.


title: Tariff

text: A 2021 study found that across 151 countries over the period 1963–2014, "tariff increases are associated with persistent, economically and statistically significant declines in domestic output and productivity, as well as higher unemployment and inequality, real exchange rate appreciation, and insignificant changes to the trade balance."


title: Tariff

text: For economic efficiency, "free trade" is often the best policy, however levying a tariff is sometimes "second best".


title: Tariff

text: A tariff is called an optimal tariff if it is set to maximize the welfare of the country imposing the tariff. It is a tariff derived by the intersection between the "trade indifference curve" of that country and the offer curve of another country. In this case, the welfare of the other country grows worse simultaneously, thus the policy is a kind of "beggar thy neighbor policy". If the offer curve of the other country is a line through the origin point, the original country is in the "condition of a small country", so any tariff worsens the welfare of the original country.


title: Tariff

text: It is possible to levy a tariff as a political policy choice, and to consider a theoretical optimum tariff rate. However, imposing an optimal tariff will often lead to the foreign country increasing their tariffs as well, leading to a loss of welfare in both countries. When countries impose tariffs on each other, they will reach a position off the contract curve, meaning that both countries' welfare could be increased by reducing tariffs.


title: Tariff

text: The tariff has been used as a political tool to establish an independent nation; for example, the United States Tariff Act of 1789, signed specifically on July 4, was called the "Second Declaration of Independence" by newspapers because it was intended to be the economic means to achieve the political goal of a sovereign and independent United States.


title: Tariff

text: The political impact of tariffs is judged depending on the political perspective; for example the 2002 United States steel tariff imposed a 30% tariff on a variety of imported steel products for a period of three years and American steel producers supported the tariff.


title: Tariff

text: Tariffs can emerge as a political issue prior to an election. In the leadup to the 2007 Australian Federal election, the Australian Labor Party announced it would undertake a review of Australian car tariffs if elected. The Liberal Party made a similar commitment, while independent candidate Nick Xenophon announced his intention to introduce tariff-based legislation as "a matter of urgency".


title: Tariff

text: Unpopular tariffs are known to have ignited social unrest, for example the 1905 meat riots in Chile that developed in protest against tariffs applied to the cattle imports from Argentina.


title: Tariff

text: Postulated in the United States by Alexander Hamilton at the end of the 18th century, by Friedrich List in his 1841 book and by John Stuart Mill, the argument made in favour of this category of tariffs was this: should a country wish to develop a new economic activity on its soil, it would have to temporarily protect it. In their view, it is legitimate to protect certain activities by customs barriers in order to give them time to grow, to reach a sufficient size and to benefit from economies of scale through increased production and productivity gains. This would allow them to become competitive in order to face international competition. Indeed, a company needs to reach a certain production volume to be profitable in order to compensate for its fixed costs. Without protectionism, foreign products which are already profitable because of the volume of production already carried out on their soil would arrive in the country in large quantities at a lower price than local production. The recipient country's nascent industry would quickly disappear. A firm already established in an industry is more efficient because it is more adapted and has greater production capacity. New firms therefore suffer losses due to a lack of competitiveness linked to their 'apprenticeship' or catch-up period. By being protected from this external competition, firms can therefore establish themselves on their domestic market. As a result, they benefit from greater freedom of manoeuvre and greater certainty regarding their profitability and future development. The protectionist phase is therefore a learning period that would allow the least developed countries to acquire general and technical know-how in the fields of industrial production in order to become competitive on international market.


title: Tariff

text: According to the economists in favour of protecting industries, free trade would condemn developing countries to being nothing more than exporters of raw materials and importers of manufactured goods. The application of the theory of comparative advantage would lead them to specialize in the production of raw materials and extractive products and prevent them from acquiring an industrial base. Protection of infant industries (e.g. through tariffs on imported products) would therefore be essential for developing countries to industrialize and escape their dependence on the production of raw materials.


title: Tariff

text: Economist Ha-Joon Chang argues that most of today's developed countries have developed through policies that are the opposite of free trade and laissez-faire. According to him, when they were developing countries themselves, almost all of them actively used interventionist trade and industrial policies to promote and protect infant industries. Instead, they would have encouraged their domestic industries through tariffs, subsidies and other measures. In his view, Britain and the United States have not reached the top of the global economic hierarchy by adopting free trade. In fact, these two countries would have been among the greatest users of protectionist measures, including tariffs. As for the East Asian countries, he points out that the longest periods of rapid growth in these countries do not coincide with extended phases of free trade, but rather with phases of industrial protection and promotion. Interventionist trade and industrial policies would have played a crucial role in their economic success. These policies would have been similar to those used by Britain in the 18th century and the United States in the 19th century. He considers that infant industry protection policy has generated much better growth performance in the developing world than free trade policies since the 1980s.


title: Tariff

text: In the second half of the 20th century, Nicholas Kaldor takes up similar arguments to allow the conversion of ageing industries. In this case, the aim was to save an activity threatened with extinction by external competition and to safeguard jobs. Protectionism must enable ageing companies to regain their competitiveness in the medium term and, for activities that are due to disappear, it allows the conversion of these activities and jobs.


title: Tariff

text: Sub-Saharan African countries have a lower income per capita in 2003 than 40 years earlier (Ndulu, World Bank, 2007, p. 33). Per capita income increased by 37% between 1960 and 1980 and fell by 9% between 1980 and 2000. Africa's manufacturing sector's share of GDP decreased from 12% in 1980 to 11% in 2013. In the 1970s, Africa accounted for more than 3% of world manufacturing output, and now accounts for 1.5%. In an Op ed article for "The Guardian" (UK), Ha-Joon Chang argues that these downturns are the result of free trade policies, and elsewhere attributes successes in some African countries such as Ethiopia and Rwanda to their abandonment of free trade and adoption of a "developmental state model".


title: Tariff

text: The poor countries that have succeeded in achieving strong and sustainable growth are those that have become mercantilists, not free traders: China, South Korea, Japan, Taiwan. Thus, whereas in the 1990s, China and India had the same GDP per capita, China followed a much more mercantilist policy and now has a GDP per capita three times higher than India's.


title: Tariff

text: Indeed, a significant part of China's rise on the international trade scene does not come from the supposed benefits of international competition but from the relocations practiced by companies from developed countries. Dani Rodrik points out that it is the countries that have systematically violated the rules of globalisation that have experienced the strongest growth.


title: Tariff

text: The 'dumping' policies of some countries have also largely affected developing countries. Studies on the effects of free trade show that the gains induced by WTO rules for developing countries are very small. This has reduced the gain for these countries from an estimated in the 2003 LINKAGE model to in the 2005 GTAP model. The 2005 LINKAGE version also reduced gains to 90 billion. As for the "Doha Round", it would have brought in only to developing countries (including China...) according to the GTAP model. However, it has been argued that the models used are actually designed to maximize the positive effects of trade liberalization, that they are characterized by the absence of taking into account the loss of income caused by the end of tariff barriers.


title: Tariff

text: At the beginning of his career, Keynes was an economist close to Alfred Marshall, deeply convinced of the benefits of free trade. From the crisis of 1929 onwards, noting the commitment of the British authorities to defend the gold parity of the pound sterling and the rigidity of nominal wages, he gradually adhered to protectionist measures.


title: Tariff

text: On 5 November 1929, when heard by the Macmillan Committee to bring the British economy out of the crisis, Keynes indicated that the introduction of tariffs on imports would help to rebalance the trade balance. The committee's report states in a section entitled "import control and export aid", that in an economy where there is not full employment, the introduction of tariffs can improve production and employment. Thus the reduction of the trade deficit favours the country's growth.


title: Tariff

text: In January 1930, in the Economic Advisory Council, Keynes proposed the introduction of a system of protection to reduce imports. In the autumn of 1930, he proposed a uniform tariff of 10% on all imports and subsidies of the same rate for all exports. In the "Treatise on Money", published in the autumn of 1930, he took up the idea of tariffs or other trade restrictions with the aim of reducing the volume of imports and rebalancing the balance of trade.


title: Tariff

text: On 7 March 1931, in the "New Statesman and Nation", he wrote an article entitled "Proposal for a Tariff Revenue". He pointed out that the reduction of wages led to a reduction in national demand which constrained markets. Instead, he proposes the idea of an expansionary policy combined with a tariff system to neutralise the effects on the balance of trade. The application of customs tariffs seemed to him "unavoidable, whoever the Chancellor of the Exchequer might be".Thus, for Keynes, an economic recovery policy is only fully effective if the trade deficit is eliminated. He proposed a 15% tax on manufactured and semi-manufactured goods and 5% on certain foodstuffs and raw materials, with others needed for exports exempted (wool, cotton).


title: Tariff

text: In 1932, in an article entitled "The Pro- and Anti-Tariffs", published in "The Listener", he envisaged the protection of farmers and certain sectors such as the automobile and iron and steel industries, considering them indispensable to Britain.


title: Tariff

text: In the post-crisis situation of 1929, Keynes judged the assumptions of the free trade model unrealistic. He criticised, for example, the neoclassical assumption of wage adjustment.


title: Tariff

text: As early as 1930, in a note to the Economic Advisory Council, he doubted the intensity of the gain from specialisation in the case of manufactured goods. While participating in the MacMillan Committee, he admitted that he no longer "believed in a very high degree of national specialisation" and refused to "abandon any industry which is unable, for the moment, to survive". He also criticised the static dimension of the theory of comparative advantage, which, in his view, by fixing comparative advantages definitively, led in practice to a waste of national resources.


title: Tariff

text: In the Daily Mail of 13 March 1931, he called the assumption of perfect sectoral labour mobility "nonsense" since it states that a person made unemployed contributes to a reduction in the wage rate until he finds a job. But for Keynes, this change of job may involve costs (job search, training) and is not always possible. Generally speaking, for Keynes, the assumptions of full employment and automatic return to equilibrium discredit the theory of comparative advantage.


title: Tariff

text: In July 1933, he published an article in the "New Statesman and Nation" entitled "National Self-Sufficiency", in which he criticised the argument of the specialisation of economies, which is the basis of free trade. He thus proposed the search for a certain degree of self-sufficiency. Instead of the specialisation of economies advocated by the Ricardian theory of comparative advantage, he prefers the maintenance of a diversity of activities for nations. In it he refutes the principle of peacemaking trade. His vision of trade became that of a system where foreign capitalists compete for new markets. He defends the idea of producing on national soil when possible and reasonable and expresses sympathy for the advocates of protectionism.


title: Tariff

text: Later, Keynes had a written correspondence with James Meade centred on the issue of import restrictions. Keynes and Meade discussed the best choice between quota and tariff. In March 1944 Keynes began a discussion with Marcus Fleming after the latter had written an article entitled "Quotas versus depreciation". On this occasion, we see that he has definitely taken a protectionist stance after the Great Depression. He considered that quotas could be more effective than currency depreciation in dealing with external imbalances. Thus, for Keynes, currency depreciation was no longer sufficient and protectionist measures became necessary to avoid trade deficits. To avoid the return of crises due to a self-regulating economic system, it seemed essential to him to regulate trade and stop free trade (deregulation of foreign trade).


title: Tariff

text: He points out that countries that import more than they export weaken their economies. When the trade deficit increases, unemployment rises and GDP slows down. And surplus countries exert a "negative externality" on their trading partners. They get richer at the expense of others and destroy the output of their trading partners. John Maynard Keynes believed that the products of surplus countries should be taxed to avoid trade imbalances. Thus he no longer believes in the theory of comparative advantage (on which free trade is based) which states that the trade deficit does not matter, since trade is mutually beneficial.


title: Tariff

text: This also explains his desire to replace the liberalisation of international trade (Free Trade) with a regulatory system aimed at eliminating trade imbalances in his proposals for the Bretton Woods Agreement.


title: Tariff

text: Trade liberalization can sometimes result in large and unequally distributed losses and gains, and can, in the short run, cause significant economic dislocation of workers in import-competing sectors.


title: Code-division multiple access

text: Code-division multiple access (CDMA) is a channel access method used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communication channel. This allows several users to share a band of frequencies (see bandwidth). To permit this without undue interference between the users, CDMA employs spread spectrum technology and a special coding scheme (where each transmitter is assigned a code).


title: Code-division multiple access

text: CDMA optimizes the use of available bandwidth as it transmits over the entire frequency range and does not limit the user's frequency range.


title: Code-division multiple access

text: It is used as the access method in many mobile phone standards. IS-95, also called "cdmaOne", and its 3G evolution CDMA2000, are often simply referred to as "CDMA", but UMTS, the 3G standard used by GSM carriers, also uses "wideband CDMA", or W-CDMA, as well as TD-CDMA and TD-SCDMA, as its radio technologies.


title: Code-division multiple access

text: It can be also used as a channel or medium access technology, like ALOHA for example or as a permanent pilot/signalling channel to allow users to synchronize their local oscillators to a common system frequency, thereby also estimating the channel parameters permanently.


title: Code-division multiple access

text: In these schemes, the message is modulated on a longer spreading sequence, consisting of several chips (0es and 1es). Due to their very advantageous auto- and crosscorrelation characteristics, these spreading sequences have also been used for radar applications for many decades, where they are called Barker codes (with a very short sequence length of typically 8 to 32).


title: Code-division multiple access

text: For space-based communication applications, CDMA has been used for many decades due to the large path loss and Doppler shift caused by satellite motion. CDMA is often used with binary phase-shift keying (BPSK) in its simplest form, but can be combined with any modulation scheme like (in advanced cases) quadrature amplitude modulation (QAM) or orthogonal frequency-division multiplexing (OFDM), which typically makes it very robust and efficient (and equipping them with accurate ranging capabilities, which is difficult without CDMA). Other schemes use subcarriers based on binary offset carrier modulation (BOC modulation), which is inspired by Manchester codes and enable a larger gap between the virtual center frequency and the subcarriers, which is not the case for OFDM subcarriers. Many carriers (such as AT&T and Verizon) will shut down 3G CDMA networks in 2022.


title: Code-division multiple access

text: In the US, one of the earliest descriptions of CDMA can be found in the summary report of Project Hartwell on "The Security of Overseas Transport", which was a summer research project carried out at the Massachusetts Institute of Technology from June to August 1950. Further research in the context of jamming and anti-jamming was carried out in 1952 at Lincoln Lab.


title: Code-division multiple access

text: In the Soviet Union (USSR), the first work devoted to this subject was published in 1935 by Dmitry Ageev. It was shown that through the use of linear methods, there are three types of signal separation: frequency, time and compensatory. The technology of CDMA was used in 1957, when the young military radio engineer Leonid Kupriyanovich in Moscow made an experimental model of a wearable automatic mobile phone, called LK-1 by him, with a base station. LK-1 has a weight of 3 kg, 20–30 km operating distance, and 20–30 hours of battery life. The base station, as described by the author, could serve several customers. In 1958, Kupriyanovich made the new experimental "pocket" model of mobile phone. This phone weighed 0.5 kg. To serve more customers, Kupriyanovich proposed the device, which he called "correlator." In 1958, the USSR also started the development of the "Altai" national civil mobile phone service for cars, based on the Soviet MRT-1327 standard. The phone system weighed . It was placed in the trunk of the vehicles of high-ranking officials and used a standard handset in the passenger compartment. The main developers of the Altai system were VNIIS (Voronezh Science Research Institute of Communications) and GSPI (State Specialized Project Institute). In 1963 this service started in Moscow, and in 1970 Altai service was used in 30 USSR cities.


title: Code-division multiple access

text: CDMA is a spread-spectrum multiple-access technique. A spread-spectrum technique spreads the bandwidth of the data uniformly for the same transmitted power. A spreading code is a pseudo-random code that has a narrow ambiguity function, unlike other narrow pulse codes. In CDMA a locally generated code runs at a much higher rate than the data to be transmitted. Data for transmission is combined by bitwise XOR (exclusive OR) with the faster code. The figure shows how a spread-spectrum signal is generated. The data signal with pulse duration of formula_1 (symbol period) is XORed with the code signal with pulse duration of formula_2 (chip period). (Note: bandwidth is proportional to formula_3, where formula_4 = bit time.) Therefore, the bandwidth of the data signal is formula_5 and the bandwidth of the spread spectrum signal is formula_6. Since formula_2 is much smaller than formula_1, the bandwidth of the spread-spectrum signal is much larger than the bandwidth of the original signal. The ratio formula_9 is called the spreading factor or processing gain and determines to a certain extent the upper limit of the total number of users supported simultaneously by a base station.


title: Code-division multiple access

text: Each user in a CDMA system uses a different code to modulate their signal. Choosing the codes used to modulate the signal is very important in the performance of CDMA systems. The best performance occurs when there is good separation between the signal of a desired user and the signals of other users. The separation of the signals is made by correlating the received signal with the locally generated code of the desired user. If the signal matches the desired user's code, then the correlation function will be high and the system can extract that signal. If the desired user's code has nothing in common with the signal, the correlation should be as close to zero as possible (thus eliminating the signal); this is referred to as cross-correlation. If the code is correlated with the signal at any time offset other than zero, the correlation should be as close to zero as possible. This is referred to as auto-correlation and is used to reject multi-path interference.