56 Fun Facts About Wi-Fi

What do the curved bars of the Wi-Fi icon on a phone or laptop measure?

Signal strength: the bars show how well your device hears the router, not how fast the link is, so a full set can still come with a crawling connection.

The two radio bands Wi-Fi most commonly uses are 5 GHz and which other?

2.4 GHz: US regulators opened the band to licence-free radio gear in 1985, so any maker could build for it without buying airwaves, and gadgets of every kind have crowded in since.

Which common kitchen appliance can disrupt nearby Wi-Fi while it is running?

Microwave oven: it heats food with the same band of waves most Wi-Fi uses, and the oven was there first, since that band was set aside in 1947 for microwave heating.

Which chip maker's Centrino brand, launched in 2003, put built-in Wi-Fi into millions of laptops?

Intel: Wi-Fi was far from a standard laptop feature at the time, so Centrino bundled it with the processor and a vast advertising blitz had buyers asking for it by name.

The name Wi-Fi was partly chosen because it echoes which older consumer term?

Hi-Fi: the rhyme was the point, and by one founder's account the name stands for nothing, with the 'Wireless Fidelity' slogan added afterwards to reassure nervous board members.

What shape is the Wi-Fi Alliance's certification logo?

A yin-yang: only products that pass the Alliance's interoperability testing may carry it, so buyers can trust gear from different makers to work together.

Why do devices often join an 'evil twin' hotspot rather than the real network it copies?

Its signal is stronger: attackers sit close to their targets, so the copy outshouts the real hotspot and some devices then join it automatically.

The NCR team whose wireless networking gear paved the way for Wi-Fi worked in Nieuwegein, in which country?

Netherlands: NCR wanted wireless links for its cash registers, so it asked one of its engineers to start work on an industry-wide wireless standard.

Why does 5 GHz Wi-Fi usually reach fewer rooms than a router's lower band?

Higher frequencies weaken faster: walls and floors absorb more of a 5 GHz signal, so for distant rooms the lower band is the better pick.

Which Australian science agency built a wireless LAN test bed in 1992 and later earned hundreds of millions from Wi-Fi patents?

CSIRO: its team tamed reverberation, radio waves bouncing off indoor surfaces and distorting the signal, which had made fast indoor wireless links so hard to build.

John O'Sullivan's Australian team adapted a technique for reducing multipath interference that he had originally developed for what field?

Radio astronomy: O'Sullivan had used that maths to sharpen radio-telescope images, and the patent it produced now underpins Wi-Fi in phones, laptops and TVs.

Which video game company was among the firms that paid the Australian science agency in 2009 to settle Wi-Fi patent claims?

Nintendo: it joined HP, Microsoft and Intel in paying over $200 million, and a second wave of claims drew more than $220 million from other firms in 2012.

Ad hoc Wi-Fi, which needs no router, let nearby friends play each other on which kind of device?

Handheld game consoles: Sony's PSP had an ad hoc mode that let nearby systems talk straight to each other, so friends in the same room could play together with no router or internet connection.

What did Apple call the Wi-Fi feature it launched with its iBook laptop in 1999?

AirPort: Apple teamed with Lucent to build it, and once the iBook showed laptops could go online without a cable, other computer makers quickly followed.

What does the 6 in the name Wi-Fi 6 stand for?

Sixth generation: in 2018 the Wi-Fi Alliance swapped engineering codes for plain numbers so that shoppers could tell at a glance which gear was newer.

Wi-Fi 6E extends Wi-Fi 6 into which additional frequency band?

6 GHz: US regulators opened the band to Wi-Fi in 2020, giving new devices a wide stretch of fresh airwaves away from the congestion that slows older networks.

Which tech giant bought the home Wi-Fi router start-up Eero in 2019?

Amazon: it said the deal would help customers connect smart-home devices more easily, since owning the router makes its Alexa gadgets simpler to set up.

Ultra-fast, short-range Wi-Fi that uses the 60 GHz millimetre-wave band is sold under what brand name?

WiGig: its signals carry several gigabits a second but cannot get through walls, so it is used for cable-free links within one room, such as laptop docks and virtual-reality headsets.

By 2025, the fastest Wi-Fi versions at close range could reach roughly what speed?

23 Gbit/s: that is over ten thousand times the speed of the original 1997 standard, yet the following version, Wi-Fi 8, aims for steadier connections rather than a higher peak.

On a router's label or a phone's Wi-Fi settings, what does the term SSID refer to?

The network's name: SSID stands for service set identifier, and although a router can stop broadcasting it, hiding the name is only a minimal security measure that freely available tools defeat.

Which router feature gets a device online but blocks it from your own computers and smart devices?

Guest network: it has its own name and password, so visitors never learn your main one, and malware on a friend's phone cannot reach the devices on your own network.

Which address is built into a Wi-Fi device at the factory rather than set by the network?

MAC address: because it never changed, networks could use it to follow a phone from place to place, so Apple and Android devices now show each network a different, randomised one.

Before a Wi-Fi device transmits on a shared channel, what must it do first?

Check the airwaves are clear: a radio cannot hear a clash while it is sending, so Wi-Fi listens first, then waits a random moment, which is why crowded networks slow down.

Which is the only country where Wi-Fi may use channel 14, the highest in its lower band?

Japan: the United States allows 11 channels and Europe 13, and even in Japan channel 14 works only with the oldest, slowest kind of Wi-Fi, so modern devices rarely use it.

The typical indoor range of a Wi-Fi access point is about how far?

20 metres: walls, floors and furniture soak up the signal indoors, which is why the same access point reaches farther in the open air.

In 2015 Britain's telecoms regulator warned that which Christmas decoration could slow down home Wi-Fi?

Fairy lights: Ofcom made the festive warning while launching an app to test home Wi-Fi, after finding that connections in six million homes and offices ran slower than they should.

Wi-Fi's original encryption scheme, which free tools can now crack within minutes, was called what?

WEP: short for Wired Equivalent Privacy, it promised the privacy of a cable, but flaws in its design soon surfaced and it was officially retired in 2004.

Public Wi-Fi is now usually safe, say US consumer regulators, because most websites protect your data with what?

HTTPS encryption: the padlock in the address bar means data is scrambled between you and the site, so the old advice to stay off café Wi-Fi is now mostly out of date.

The 2017 KRACK attack broke which security standard, then protecting nearly every home Wi-Fi network?

WPA2: the weakness lay in the standard itself rather than in any one product, so nearly every phone, laptop and router in the world needed a security update.

In 2010 Google admitted that which of its services had accidentally gathered data from unencrypted home Wi-Fi networks?

Street View: its camera cars also logged Wi-Fi networks to help phones work out where they were, but a software mistake saved snippets of what was sent over unprotected ones.

A flaw revealed in 2011 let attackers guess within hours the PIN behind which router convenience feature?

Wi-Fi Protected Setup: the router confirmed the eight-digit PIN in two halves, cutting the guesses needed to about 11,000, so owners were told to switch the feature off.

What is the name for the practice of hunting out and mapping other people's Wi-Fi networks?

Wardriving: it is seen as the wireless heir of wardialing, the trick in the 1983 film WarGames where a computer phones number after number hunting for a modem.

Which company's blue WRT54G router won a cult following because owners could swap its software for their own?

Linksys: when a redesign shut out hobbyists' software, the firm brought the old design back in 2005, and it was still selling more than a decade later.

Which coffee chain announced in 2001 that it would bring Wi-Fi to all its North American shops?

Starbucks: the early service was not free, with customers paying by the minute or the month, and the chain only made Wi-Fi free in all its US shops in 2010.

Which university's Wireless Andrew project, begun in 1993, made it the world's first wireless campus?

Carnegie Mellon: its campus network was named Andrew after both Andrew Carnegie and Andrew Mellon, and the wireless version was running years before the Wi-Fi brand existed.

In the mid-2010s, crowds gathered in which country's public parks to get online at newly installed state Wi-Fi hotspots?

Cuba: for many people the parks offered their first way onto the internet, and families gathered there with phones and laptops to call relatives living abroad.

New York City's LinkNYC project replaced what with public Wi-Fi kiosks?

Old phone booths: from 2015 the city's payphones gave way to kiosks with free Wi-Fi, calls and charging, paid for by the adverts on their screens, and the last street payphone went in 2022.

Which international service lets students log on to Wi-Fi at other universities using their home campus login?

Eduroam: the visitor's own university checks the password, so one login works at tens of thousands of campuses and libraries worldwide, an idea first tried by European research networks in 2002.

Ending your Wi-Fi name with which suffix keeps your router out of Google's location database?

_nomap: phones find themselves when GPS is weak by noting which known routers are nearby, so in 2011 Google let owners opt a router out simply by renaming their network.

Which Wi-Fi standard lets a phone reach a printer or TV without any router?

Wi-Fi Direct: one device acts as a temporary access point for the other, and the Miracast standard that mirrors a phone's screen on a TV is built on top of it.

Film star Hedy Lamarr and composer George Antheil patented a frequency-hopping radio system in the Second World War to do what?

Guiding torpedoes: hopping between frequencies was meant to stop the enemy jamming the control signal, but the US Navy never adopted it during the war and the pair never earned a penny from it.

ALOHAnet, a 1971 radio network from the University of Hawaii, inspired which wired networking technology?

Ethernet: Bob Metcalfe read a paper about the Hawaiian network, fixed the flaws in its scheme of resending after a random wait, and used the result to wire up the new personal computers at Xerox.

Which short-range wireless standard is named after a 10th-century Danish king?

Bluetooth: King Harald Bluetooth united Denmark and Norway, so an Intel engineer borrowed his nickname for a technology meant to unite computers and phones, and the logo merges the runes of his initials.

Harald Haas coined the name Li-Fi, for data sent by light, at which 2011 event?

A TEDGlobal talk in Edinburgh: on stage Haas sent data through the flicker of a single LED, too fast for the eye to see, and because light cannot pass through walls the signal stays private.

What health effects does the World Health Organization anticipate from the radio signals of Wi-Fi networks and phone masts?

None is expected: the WHO found that exposure in public places is normally thousands of times below safety limits, and that the body absorbs up to five times more signal from FM radio and television.

Which kind of home Wi-Fi system uses several units placed around the house that relay traffic to one another?

Mesh network: each unit passes traffic on to its neighbours, so coverage reaches rooms a single router cannot, and if one unit fails the others simply find a new route.

Sharing your phone's mobile data connection with a laptop or tablet is known as what?

Tethering: the phone becomes a pocket Wi-Fi hotspot for nearby devices, which is why some mobile carriers cap the feature or charge extra for it.

Roughly how many Wi-Fi devices were shipped worldwide in 2019 alone?

4 billion is the closest: counts for the year run from about 3 billion to over 4 billion, roughly one new Wi-Fi device for every two or three people on Earth.

What is the name for the system that makes you sign in before hotel or café Wi-Fi will work?

Captive portal: the network blocks everything else until you accept its terms or sign in, which is why your phone opens a login page by itself as soon as you connect.

In 2014 US regulators fined which hotel chain $600,000 for jamming guests' personal Wi-Fi hotspots at a convention centre?

Marriott: a guest at its Nashville resort complained that a personal hotspot would not connect, and after the fine and a backlash from customers and the press the chain promised to stop blocking them.

Which tiny Pacific island nation got free nationwide Wi-Fi in 2003 in a deal over its .nu internet addresses?

Niue: the addresses sell well in Sweden, where nu means now, but the island's government later went to court, saying the free internet was worth far less than the millions the addresses had earned.

Which aerospace giant began selling in-flight Wi-Fi to airline passengers in 2004, only to scrap the service two years later?

Boeing: its Connexion service, launched with Lufthansa, beamed the internet to jets by satellite, but the firm said the market had not materialised and wrote off up to $320 million.

A Latin American networking school beamed Wi-Fi a record 382 km between two mountains in 2007 in which country?

Venezuela: Ermanno Pietrosemoli's team linked the 4,200-metre Andean site of El Águila to distant Platillón using low-cost routers and dish antennas, and the link even carried video, if not always steadily.

Swedish engineers once held a Wi-Fi link across more than 300 km by aiming at what kind of target?

A stratospheric balloon: floating almost 30 km up, it stayed in plain view of the ground station near its Arctic launch site, so the link held for 310 km as it drifted from Sweden into Finland.

What is the name for using a neighbour's Wi-Fi connection without their permission?

Piggybacking: anyone within range of a router left without a password can use its connection, sometimes by accident when a laptop joins by itself, and whether that is a crime depends on the country.

What is the main drawback of each extra hop added by a wireless range extender?

Increased latency and lower throughput: an extender must receive each packet and then send it on again over the same airwaves, so the speed available through it is roughly halved.