Mobile phone

• 1. The Call That Started It All

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  On the 3rd of April 1973, Martin Cooper of Motorola stood on a street in New York City holding a handset that weighed about 2 kilograms, roughly 4.4 pounds. He dialed Joel S. Engel, a rival who worked for AT&T. Cooper told him, "I'm calling you on a cell phone, but a real cell phone, a personal, handheld, portable cell phone." It was the first call ever made on such a device. That single moment hints at a much longer struggle. How did a 2 kilogram brick demonstrated on a sidewalk become a device that, by 2024, claimed over 9.1 billion subscriptions worldwide, enough to give one to every person on Earth? What had to be invented before a phone could leave a car, fit in a pocket, and follow a person as they walked? And how did a tool built for talking come to carry banking, photography, news, and the location of nearly everyone who owns one?

• 2. Carving Space From The Air

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  The radio spectrum allocated to mobile services is limited, and that scarcity shaped everything. Former systems covered a whole service area with one or two powerful base stations, each reaching up to tens of kilometers, using only a few sets of radio channels. Once those channels were in use, no further customers could be served until someone hung up. The cellular network solved this by dividing a service area into many small cells, each with its own base station reaching on the order of a kilometer. When a subscriber uses a channel in one cell, that frequency goes unavailable in the local cell and adjacent cells. Cells further away reuse the same channel without interference, since the handset is too far to be detected. This frequency reuse lets thousands of subscribers converse at once within a single geographic area. Each cell is typically covered by three towers placed at different locations, and the towers connect to the phone network and the internet by wired connections. Because each cell can handle only a maximum number of phones at once, cells are sized to expected demand and shrink in dense cities. To absorb sudden surges at special events or disasters, companies bring a truck loaded with equipment to host the abnormally high traffic.

• 3. The Generations Game

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  Bell System's Mobile Telephone Service and its successor, the Improved Mobile Telephone Service, were early zeroth-generation systems that were not cellular, supported only a few simultaneous calls, and were very expensive. In those earliest setups all control was manual. A customer searched for an unoccupied channel and spoke to a mobile operator, who connected the call to a landline or another mobile and later recorded the billing by hand. In 1979, Nippon Telegraph and Telephone launched the world's first commercial automated cellular network, an analog first-generation system, in Japan. In 1981 the Nordic Mobile Telephone system launched simultaneously in Denmark, Finland, Norway, and Sweden. Then in 1991, second-generation digital cellular technology arrived in Finland through Radiolinja on the GSM standard, sparking competition as new operators challenged the analog incumbents. The first version of the GSM standard ran to 6,000 pages, and a 1987 Memorandum of Understanding among 13 European countries committed them to a commercial service by 1991. The IEEE and RSE later awarded Thomas Haug and Philippe Dupuis the 2018 James Clerk Maxwell medal for their work on that first digital standard. In 2001, NTT DoCoMo launched third-generation service in Japan on the WCDMA standard, bringing mobile broadband of several megabits per second. Fourth-generation arrived when TeliaSonera launched the first publicly available LTE service in Scandinavia in 2009. Deployment of fifth-generation networks began worldwide in 2019, with the 5G NR standard aiming for a network latency of 1 millisecond.

• 4. Anatomy Of A Handset

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  Every mobile phone shares a small set of common parts. At its core sits a central processing unit, a microprocessor fabricated on a metal-oxide-semiconductor integrated circuit chip, optimised to run in low power environments. A modern handset draws power from a lithium-ion battery, while older handsets used nickel-metal hydride cells. The input mechanism is a keypad on feature phones and a touch screen, typically using capacitive sensing, on most smartphones. The display, usually a liquid-crystal display or an organic light-emitting diode panel, echoes typing and shows messages and contacts. The first GSM phones and many feature phones used NOR flash memory, which let processor instructions run directly in place and gave short boot times. Smartphones adopted NAND flash for its larger capacity and lower cost, accepting longer boot times because instructions must first be copied to RAM before running. Screen size became its own measure of identity. Feature phones generally stay below 3.5 inches, phones above 5.2 inches are often called "phablets," and smartphones over 4.5 inches are commonly hard to use with one hand. A typical mobile phone battery lasts about two to three years and is designed to endure between 500 and 2,500 charge cycles. Lithium-ion cells perform best kept between 30 percent and 80 percent of full charge. Future batteries are expected to use silicon-carbon and solid-state designs promising higher energy densities and longer lifespans.

• 5. The Card That Knows You

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  About the size of a small postage stamp, the Subscriber Identity Module sits usually beneath the battery in the rear of the unit. The SIM securely stores the service-subscriber key, known as the IMSI, along with the Ki used to identify and authenticate the user. Because the card holds the identity, a user can change phones simply by moving the SIM from one device to another, unless a SIM lock prevents it. The first SIM card was made in 1991 by the Munich smart card maker Giesecke & Devrient for the Finnish operator Radiolinja. A hybrid phone can hold up to four SIM cards, each giving the phone a different device identifier, and SIM and R-UIM cards can be mixed to reach both GSM and CDMA networks. From 2010 onward such multi-card phones grew popular in emerging markets, driven by the desire to obtain the lowest calling costs. The card also acts as a tripwire. When the operating system detects a SIM being removed, it may deny further operation until a reboot.

• 6. More Than A Phone

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  In 1992, the first SMS message was sent from a computer to a mobile phone in the United Kingdom, and in 1993 the first person-to-person text travelled phone to phone in Finland. The first mobile news service delivered by SMS launched in Finland in 2000, and Multimedia Messaging Service followed in March 2002. Money soon moved across the same channels. Mobile payments were first trialled in Finland in 1998, when two Coca-Cola vending machines in Espoo were enabled to take SMS payments, and in 1999 the Philippines launched its first commercial mobile payment systems through the operators Globe and Smart. Kenya's M-PESA service lets customers of the operator Safaricom hold cash balances recorded on their SIM cards, depositing or withdrawing at retail outlets across the country and transferring money person to person. Software turned the device into a platform. Apple's App Store launched for the iPhone and iPod Touch in July 2008, popularizing manufacturer-hosted distribution of third-party apps for a single platform. Android has been the best-selling smartphone system worldwide since 2011, and as of March 2025 it held 71.9 percent of the market while iOS held 27.7 percent. The cultural ripples ran wide, from the cell phone novel, the first literary genre to emerge from the cellular age, to the rise of SMS language and the growing popularity of emojis.

• 7. The Cost Of Connection

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  Around 40 to 50 percent of the environmental impact of a mobile phone occurs during the manufacture of its printed wiring boards and integrated circuits. The average user replaces their handset every 11 to 18 months, and the discarded phones feed a stream of electronic waste. Manufacturers within Europe fall under the WEEE directive, and Apple Inc. built an advanced robotic disassembler and sorter called Liam to recycle outdated or broken iPhones. The same devices made people easier to track. While a phone is turned on, its geographical location can be determined whether or not it is in use, through multilateration that measures the differences in time for a signal to reach several nearby cell towers. Service providers, law enforcement, and governments can all follow a user's movements, and hackers who obtain a subscriber's phone number have read messages and recorded calls. Theft became its own epidemic. According to the Federal Communications Commission, one out of three robberies involves the theft of a cellular phone, and San Francisco police data showed half of all robberies in 2012 were phone thefts. On the 10th of June 2013, Apple announced it would install a "kill switch" on its next iPhone operating system, due to debut that October. The human cost reaches deeper still. Demand for metals used in phones and other electronics fuelled the Second Congo War, which claimed almost 5.5 million lives, and the company Fairphone has worked to build a phone free of conflict minerals.

• 8. Drivers, Walkers, And The Rules

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  In September 2010, the US National Highway Traffic Safety Administration reported that 995 people were killed by drivers distracted by cell phones. A simulation study at the University of Utah found a sixfold increase in distraction-related accidents when texting, and a 2011 study reported that over 90 percent of surveyed college students text while driving. Rules vary sharply by place. Egypt, Israel, Japan, Portugal, and Singapore ban both handheld and hands-free use, while the United Kingdom, France, and many US states ban only handheld use. New Zealand has banned handheld use since the 1st of November 2009, and in the United Kingdom from the 27th of February 2007 motorists caught with a handheld phone gained three penalty points plus a 60 pound fine. Walking carried its own toll. Between 2011 and 2019, an estimated 30,000 walking injuries in the US were related to cellphone use, and countries such as China and the Netherlands introduced special lanes for smartphone users. Other limits answered belief and custom. The Orthodox Jewish rabbinate in Britain approved a brand of "Kosher" phones with no texting capabilities, worried that texting by youths could waste time and lead to immodest communication, and some vendors reported good sales to adults who simply preferred the simplicity. A study by the London School of Economics found that banning phones in schools could raise pupils' performance by the equivalent of one extra week of schooling per year, a reminder that the device's reach is still being measured.