Bluetooth specification

 BLUETOOTH HISTORY

Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances (using short-wavelength radio transmissions in the ISM band from 2400–2480 MHz) from fixed and mobile devices, creating personal area networks (PANs) with high levels of security. Created by telecoms vendor Ericsson in 1994, it was originally conceived as a wireless alternative to RS-232 data cables. It can connect several devices, overcoming problems of synchronization.
Bluetooth is managed by the Bluetooth Special Interest Group, which has more than 15,000 member companies in the areas of telecommunication, computing, networking, and consumer electronics. The SIG oversees the development of the specification, manages the qualification program, and protects the trademarks. To be marketed as a Bluetooth device, it must be qualified to standards defined by the SIG. A network of patents is required to implement the technology and are only licensed to those qualifying devices; thus the protocol, whilst open, may be regarded as proprietary.

Implementation

Bluetooth uses a radio technology called frequency-hopping spread spectrum, which chops up the data being sent and transmits chunks of it on up to 79 bands (1 MHz each; centered from 2402 to 2480 MHz) in the range 2,400–2,483.5 MHz (allowing for guard bands). This range is in the globally unlicensed Industrial, Scientific and Medical (ISM) 2.4 GHz short-range radio frequency band. It usually performs 800 hops per second, with AFH enabled.
Originally Gaussian frequency-shift keying (GFSK) modulation was the only modulation scheme available; subsequently, since the introduction of Bluetooth 2.0+EDR, π/4-DQPSK and 8DPSK modulation may also be used between compatible devices. Devices functioning with GFSK are said to be operating in basic rate (BR) mode where an instantaneous data rate of 1 Mbit/s is possible. The term Enhanced Data Rate (EDR) is used to describe π/4-DPSK and 8DPSK schemes, each giving 2 and 3 Mbit/s respectively. The combination of these (BR and EDR) modes in Bluetooth radio technology is classified as a "BR/EDR radio".
Bluetooth is a packet-based protocol with a master-slave structure. One master may communicate with up to 7 slaves in a piconet; all devices share the master's clock. Packet exchange is based on the basic clock, defined by the master, which ticks at 312.5 µs intervals. Two clock ticks make up a slot of 625 µs; two slots make up a slot pair of 1250 µs. In the simple case of single-slot packets the master transmits in even slots and receives in odd slots; the slave, conversely, receives in even slots and transmits in odd slots. Packets may be 1, 3 or 5 slots long but in all cases the master transmit will begin in even slots and the slave transmit in odd slots.
Bluetooth provides a secure way to connect and exchange information between devices such as faxes, mobile phones, telephones, laptops, personal computers, printers, Global Positioning System (GPS) receivers, digital cameras, and video game consoles.

Communication and connection

A master Bluetooth device can communicate with a maximum of seven devices in a piconet (an ad-hoc computer network using Bluetooth technology), though not all devices support this limit. The devices can switch roles, by agreement, and the slave can become the master (for example, a headset initiating a connection to a phone will necessarily begin as master, as initiator of the connection; but may subsequently prefer to be slave).
The Bluetooth Core Specification provides for the connection of two or more piconets to form a scatternet, in which certain devices simultaneously play the master role in one piconet and the slave role in another.
At any given time, data can be transferred between the master and one other device (except for the little-used broadcast mode). The master chooses which slave device to address; typically, it switches rapidly from one device to another in a round-robin fashion. Since it is the master that chooses which slave to address, whereas a slave is (in theory) supposed to listen in each receive slot, being a master is a lighter burden than being a slave. Being a master of seven slaves is possible; being a slave of more than one master is difficult. The specification is vague as to required behaviour in scatternets.
Many USB Bluetooth adapters or "dongles" are available, some of which also include an IrDA adapter. Older (pre-2003) Bluetooth dongles, however, have limited capabilities, offering only the Bluetooth Enumerator and a less-powerful Bluetooth Radio incarnation. Such devices can link computers with Bluetooth with a distance of 100 meters, but they do not offer as many services as modern adapters do.

Uses

Bluetooth is a standard wire-replacement communications protocol primarily designed for low power consumption, with a short range (power-class-dependent, but effective ranges vary in practice; see table below) based on low-cost transceiver microchips in each device. Because the devices use a radio (broadcast) communications system, they do not have to be in visual line of sight of each other, however a quasi optical wireless path must be viable.

Class	Maximum permitted power		Range (m)
	(mW)	(dBm)
Class 1	100	20	~100
Class 2	2.5	4	~10
Class 3	1	0	~5

The effective range varies due to propagation conditions, material coverage, production sample variations, antenna configurations and battery conditions. In most cases the effective range of class 2 devices is extended if they connect to a class 1 transceiver, compared to a pure class 2 network. This is accomplished by the higher sensitivity and transmission power of Class 1 devices.

Version	Data rate	Maximum application throughput
Version 1.2	1 Mbit/s	0.7 Mbit/s
Version 2.0 + EDR	3 Mbit/s	2.1 Mbit/s
Version 3.0 + HS	See Version 3.0+HS.
Version 4.0	See Version 4.0LE.

While the Bluetooth Core Specification does mandate minimums for range, the range of the technology is application specific and is not limited. Manufacturers may tune their implementations to the range needed to support individual use cases.

Bluetooth profiles

Main article: Bluetooth profile

To use Bluetooth wireless technology, a device has to be able to interpret certain Bluetooth profiles, which are definitions of possible applications and specify general behaviors that Bluetooth enabled devices use to communicate with other Bluetooth devices. These profiles include settings to parametrize and to control the communication from start. Adherence to profiles saves the time for transmitting the parameters anew before the bi-directional link becomes effective. There are a wide range of Bluetooth profiles that describe many different types of applications or use cases for devices

 List of applications

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A typical Bluetooth mobile phone headset.

• Wireless control of and communication between a mobile phone and a handsfree headset. This was one of the earliest applications to become popular.
• Wireless control of and communication between a mobile phone and a Bluetooth compatible car stereo system
• Wireless Bluetooth headset and Intercom.
• Wireless networking between PCs in a confined space and where little bandwidth is required.
• Wireless communication with PC input and output devices, the most common being the mouse, keyboard and printer.
• Transfer of files, contact details, calendar appointments, and reminders between devices with OBEX.
• Replacement of previous wired RS-232 serial communications in test equipment, GPS receivers, medical equipment, bar code scanners, and traffic control devices.
• For controls where infrared was often used.
• For low bandwidth applications where higher USB bandwidth is not required and cable-free connection desired.
• Sending small advertisements from Bluetooth-enabled advertising hoardings to other, discoverable, Bluetooth devices.
• Wireless bridge between two Industrial Ethernet (e.g., PROFINET) networks.
• Three seventh-generation game consoles, Nintendo's Wiiand Sony's PlayStation 3 and PSP Go, use Bluetooth for their respective wireless controllers.
• Dial-up internet access on personal computers or PDAs using a data-capable mobile phone as a wireless modem.
• Short range transmission of health sensor data from medical devices to mobile phone, set-top box or dedicated telehealth devices.
• Allowing a DECT phone to ring and answer calls on behalf of a nearby cell phone
• Real-time location systems (RTLS), are used to track and identify the location of objects in real-time using “Nodes” or “tags” attached to, or embedded in the objects tracked, and “Readers” that receive and process the wireless signals from these tags to determine their locations
• Personal security application on mobile phones for prevention of theft or loss of items. The protected item has a Bluetooth marker (e.g. a tag) that is in constant communication with the phone. If the connection is broken (the marker is out of range of the phone) then an alarm is raised. This can also be used as a man overboard alarm. A product using this technology has been available since 2009.

Bluetooth vs. Wi-Fi (IEEE 802.11)

Bluetooth and Wi-Fi (the brand name for products using IEEE 802.11 standards) have some similar applications: setting up networks, printing, or transferring files. Wi-Fi is intended as a replacement for cabling for general local area network access in work areas. This category of applications is sometimes called wireless local area networks (WLAN). Bluetooth was intended for portable equipment and its applications. The category of applications is outlined as the wireless personal area network (WPAN). Bluetooth is a replacement for cabling in a variety of personally carried applications in any setting and can also support fixed location applications such as smart energy functionality in the home (thermostats, etc.).
Wi-Fi is a wireless version of a common wired Ethernet network, and requires configuration to set up shared resources, transmit files, and to set up audio links (for example, headsets and hands-free devices). Wi-Fi uses the same radio frequencies as Bluetooth, but with higher power, resulting in higher bit rates and better range from the base station. The nearest equivalents in Bluetooth are the DUN profile, which allows devices to act as modem interfaces, and the PAN profile, which allows for ad-hoc networking.

Devices

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A Bluetooth USB dongle with a 100 m range. The MacBook Pro, shown, also has a built in Bluetooth adaptor.

Bluetooth exists in many products, such as the iPod Touch, Lego Mindstorms NXT, PlayStation 3, PSP Go, telephones, the Nintendo Wii, and some high definition headsets, modems, and watches. The technology is useful when transferring information between two or more devices that are near each other in low-bandwidth situations. Bluetooth is commonly used to transfer sound data with telephones (i.e., with a Bluetooth headset) or byte data with hand-held computers (transferring files).

Bluetooth protocols simplify the discovery and setup of services between devices. Bluetooth devices can advertise all of the services they provide. This makes using services easier because more of the security, network address and permission configuration can be automated than with many other network types.

Android4.0 Platform

ANDROID 4.0 VERSION(DUALPROCESSOR)

 Simple, beautiful, beyond smart

Android 4.0 builds on the things people love most about Android — easy multitasking, rich notifications, customizable home screens, resizable widgets, and deep interactivity — and adds powerful new ways of communicating and sharing.

Refined, evolved UI

Focused on bringing the power of Android to the surface, Android 4.0 makes common actions more visible and lets users navigate with simple, intuitive gestures. Refined animations and feedback throughout the system make interactions engaging and interesting. An entirely new typeface optimized for high-resolution screens improves readability and brings a polished, modern feel to the user interface.
Virtual buttons in the System Bar let users navigate instantly to Back, Home, and Recent Apps. The System Bar and virtual buttons are present across all apps, but can be dimmed by applications for full-screen viewing. Users can access each application's contextual options in the Action Bar, displayed at the top (and sometimes also at the bottom) of the screen.
Multitasking is a key strength of Android and it's made even easier and more visual on Android 4.0. The Recent Apps button lets users jump instantly from one task to another using the list in the System Bar. The list pops up to show thumbnail images of apps used recently — tapping a thumbnail switches to the app.

The Recent Apps list makes multitasking simple.

Jump to the camera or see notifications without unlocking.

For incoming calls, you can respond instantly by text.

Rich and interactive notifications let users keep in constant touch with incoming messages, play music tracks, see real-time updates from apps, and much more. On smaller-screen devices, notifications appear at the top of the screen, while on larger-screen devices they appear in the System Bar.

The All Apps launcher (left) and resizable widgets (right) give you apps and rich content from the home screen.

Home screen folders and favorites tray

New home screen folders offer a new way for users to group their apps and shortcuts logically, just by dragging one onto another. Also, in All Apps launcher, users can now simply drag an app to get information about it or immediately uninstall it, or disable a pre-installed app.
On smaller-screen devices, the home screen now includes a customizable favorites tray visible from all home screens. Users can drag apps, shortcuts, folders, and other priority items in or out of the favorites tray for instant access from any home screen.

Resizable widgets

Home screens in Android 4.0 are designed to be content-rich and customizable. Users can do much more than add shortcuts — they can embed live application content directly through interactive widgets. Widgets let users check email, flip through a calendar, play music, check social streams, and more — right from the home screen, without having to launch apps. Widgets are resizable, so users can expand them to show more content or shrink them to save space.

New lock screen actions

The lock screens now let users do more without unlocking. From the slide lock screen, users can jump directly to the camera for a picture or pull down the notifications window to check for messages. When listening to music, users can even manage music tracks and see album art.

Quick responses for incoming calls

When an incoming call arrives, users can now quickly respond by text message, without needing to pick up the call or unlock the device. On the incoming call screen, users simply slide a control to see a list of text responses and then tap to send and end the call. Users can add their own responses and manage the list from the Settings app.

Swipe to dismiss notifications, tasks, and browser tabs

Android 4.0 makes managing notifications, recent apps, and browser tabs even easier. Users can now dismiss individual notifications, apps from the Recent Apps list, and browser tabs with a simple swipe of a finger.

A spell-checker lets you find errors and fix them faster.

A powerful voice input engine lets you dictate continously.

Improved text input and spell-checking

The soft keyboard in Android 4.0 makes text input even faster and more accurate. Error correction and word suggestion are improved through a new set of default dictionaries and more accurate heuristics for handling cases such as double-typed characters, skipped letters, and omitted spaces. Word suggestion is also improved and the suggestion strip is simplified to show only three words at a time.
To fix misspelled words more easily, Android 4.0 adds a spell-checker that locates and underlines errors and suggests replacement words. With one tap, users can choose from multiple spelling suggestions, delete a word, or add it to the dictionary. Users can even tap to see replacement suggestions for words that are spelled correctly. For specialized features or additional languages, users can now download and install third-party dictionaries, spell-checkers, and other text services.

Powerful voice input engine

Android 4.0 introduces a powerful new voice input engine that offers a continuous "open microphone" experience and streaming voice recognition. The new voice input engine lets users dictate the text they want, for as long as they want, using the language they want. Users can speak continously for a prolonged time, even pausing for intervals if needed, and dictate punctuation to create correct sentences. As the voice input engine enters text, it underlines possible dictation errors in gray. After dictating, users can tap the underlined words to quickly replace them from a list of suggestions.

Data usage controls let you monitor total usage by network type and application and then set limits if needed.

Control over network data

Mobile devices can make extensive use of network data for streaming content, synchronizing data, downloading apps, and more. To meet the needs of users with tiered or metered data plans, Android 4.0 adds new controls for managing network data usage.
In the Settings app, colorful charts show the total data usage on each network type (mobile or Wi-Fi), as well as amount of data used by each running application. Based on their data plans, users can optionally set warning levels or hard limits on data usage or disable mobile data altogether. Users can also manage the background data used by individual applications as needed.

Designed for accessibility

A variety of new features greatly enhance the accessibility of Android 4.0 for blind or visually impaired users. Most important is a new explore-by-touch mode that lets users navigate without having to see the screen. Touching the screen once triggers audible feedback that identifies the UI component below; a second touch in the same component activates it with a full touch event. The new mode is especially important to support users on new devices that use virtual buttons in the System Bar, rather than dedicated hardware buttons or trackballs. Also, standard apps are updated to offer an improved accessibility experience. The Browser supports a script-based screen reader for reading favorite web content and navigating sites. For improved readability, users can also increase the default font size used across the system.
The accessibility experience begins at first setup — a simple touch gesture during setup (clockwise square from upper left) activates all accessibility features and loads a setup tutorial. Once accessibility features are active, everything visible on the screen can be spoken aloud by the standard screen reader.

Communication and sharing

Contacts and profiles are integrated across apps and social networks, for a consistent, personal experience everywhere — from incoming calls to emails.

Designed for the way people live, Android 4.0 integrates rich social communication and sharing touchpoints across the system, making it easy to talk, email, text, and share.

People and profiles

Throughout the system, a user’s social groups, profiles, and contacts are linked together and integrated for easy accessibility. At the center is a new People app that offers richer profile information, including a large profile picture, phone numbers, addresses and accounts, status updates, events, stream items, and a new button for connecting on integrated social networks.
The user's own contact information is stored in a new "Me" profile, allowing easier sharing with apps and people. All of the user's integrated contacts are displayed in an easy to manage list, including controls over which contacts are shown from any integrated account or social network. Wherever the user navigates across the system, tapping a profile photo displays Quick Contacts, with large profile pictures, shortcuts to phone numbers, text messaging, and more.

Unified calendar, visual voicemail

To help organize appointments and events, an updated Calendar app brings together personal, work, school, and social agendas. With user permission, other applications can contribute events to the calendar and manage reminders, for an integrated view across multiple calendar providers. The app is redesigned to let users manage events more easily. Calendars are color-coded and users can swipe left or right to change dates and pinch to zoom in or out agendas.
In the phone app, a new visual voicemail features integrates incoming messages, voice transcriptions, and audio files from one or more providers. Third-party applications can integrate with the Phone app to add their own voice messages, transcriptions, and more to the visual voicemail inbox.

Capture the picture you want, edit, and share instantly.

Rich and versatile camera capabilities

The Camera app includes many new features that let users capture special moments with great photos and videos. After capturing images, they can edit and share them easily with friemds.
When taking pictures, continuous focus, zero shutter lag exposure, and decreased shot-to-shot speed help capture clear, precise images. Stabilized image zoom lets users compose photos and video in the way they want, including while video is recording. For new flexibility and convenience while shooting video, users can now take snapshots at full video resolution just by tapping the screen as video continues to record.
To make it easier to take great pictures of people, built-in face detection locates faces in the frame and automatically sets focus. For more control, users can tap to focus anywhere in the preview image.
For capturing larger scenes, the Camera introduces a single-motion panorama mode. In this mode, the user starts an exposure and then slowly turns the Camera to encompass as wide a perspective as needed. The Camera assembles the full range of continuous imagery into a single panoramic photo.
After taking a picture or video, users can quickly share it by email, text message, bluetooth, social networks, and more, just by tapping the thumbnail in the camera controls.

A Photo Gallery widget on the home screen.

Redesigned Gallery app with photo editor

The Gallery app now makes it easier to manage, show, and share photos and videos. For managing collections, a redesigned album layout shows many more albums and offers larger thumbnails. There are many ways to sort albums, including by time, location, people, and tags. To help pictures look their best, the Gallery now includes a powerful photo editor. Users can crop and rotate pictures, set levels, remove red eyes, add effects, and much more. After retouching, users can select one or multiple pictures or videos to share instantly over email, text messaging, bluetooth, social networks, or other apps.
An improved Picture Gallery widget lets users look at pictures directly on their home screen. The widget can display pictures from a selected album, shuffle pictures from all albums, or show a single image. After adding the widget to the home screen, users can flick through the photo stacks to locate the image they want, then tap to load it in Gallery.

Live Effects let you change backgrounds and use Silly Faces during video.

Live Effects for transforming video

Live Effects is a collection of graphical transformations that add interest and fun to videos captured in the Camera app. For example, users can change the background behind them to any stock or custom image, for just the right setting when shooting videeo. Also available for video is Silly Faces, a set of morphing effects that use state-of-the-art face recognition and GPU filters to transform facial features. For example, you can use effects such as small eyes, big mouth, big nose, face squeeze, and more. Outside of the Camera app, Live Effects is available during video chat in the Google Talk app.

Snapping a screenshot.

Sharing with screenshots

Users can now share what's on their screens more easily by taking screenshots. Hardware buttons let them snap a screenshot and store it locally. Afterward, they can view, edit, and share the screen shot in Gallery or a similar app.

Cloud-connected experience

The Browser tabs menu (left) lets you quickly switch browser tabs. The options menu (right) gives you new ways to manage your browsing experience.

Benchmark comparisons of Android Browser.

Android has always been cloud-connected, letting users browse the web and sync photos, apps, games, email, and contacts — wherever they are and across all of their devices. Android 4.0 adds new browsing and email capabilities to let users take even more with them and keep communication organized.

Powerful web browsing

The Android Browser offers an experience that’s as rich and convenient as a desktop browser. It lets users instantly sync and manage Google Chrome bookmarks from all of their accounts, jump to their favorite content faster, and even save it for reading later in case there's no network available.
To get the most out of web content, users can now request full desktop versions of web sites, rather than their mobile versions. Users can set their preference for web sites separately for each browser tab. For longer content, users can save a copy for offline reading. To find and open saved pages, users can browse a visual list that’s included with browser bookmarks and history. For better readability and accessibility, users can increase the browser’s zoom levels and override the system default text sizes.
Across all types of content, the Android Browser offers dramatically improved page rendering performance through updated versions of the WebKit core and the V8 Crankshaft compilation engine for JavaScript. In benchmarks run on a Nexus S device, the Android 4.0 browser showed an improvement of nearly 220% over the Android 2.3 browser in the V8 Benchmark Suite and more than 35% in the SunSpider 9.1 JavaScript Benchmark. When run on a Galaxy Nexus device, the Android 4.0 browser showed improvement of nearly 550% in the V8 benchmark and nearly 70% in the SunSpider benchmark.

Improved email

In Android 4.0, email is easier to send, read, and manage. For composing email, improved auto-completion of recipients helps with finding and adding frequent contacts more quickly. For easier input of frequent text, users can now create quick responses and store them in the app, then enter them from a convenient menu when composing. When replying to a message, users can now toggle the message to Reply All and Forward without changing screens.
For easier browsing across accounts and labels, the app adds an integrated menu of accounts and recent labels. To help users locate and organize IMAP and Exchange email, the Email app now supports nested mail subfolders, each with synchronization rules. Users can also search across folders on the server, for faster results.
For enterprises, the Email app supports EAS v14. It supports EAS certificate authentication, provides ABQ strings for device type and mode, and allows automatic sync to be disabled while roaming. Administrators can also limit attachment size or disable attachments.
For keeping track of incoming email more easily, a resizable Email widget lets users flick through recent email right from the home screen, then jump into the Email app to compose or reply.

Android Beam lets users share what they are using with a single tap.

Innovation

Android is continously driving innovation forward, pushing the boundaries of communication and sharing with new capabilities and interactions.

Android Beam for NFC-based sharing

Android Beam is an innovative, convenient feature for sharing across two NFC-enabled devices, It lets people instantly exchange favorite apps, contacts, music, videos — almost anything. It’s incredibly simple and convenient to use — there’s no menu to open, application to launch, or pairing needed. Just touch one Android-powered phone to another, then tap to send.
For sharing apps, Android Beam pushes a link to the app's details page in Google Play. On the other device, the Google Play client app launches and loads the details page, for easy downloading of the app. Individual apps can build on Android Beam to add other types of interactions, such as passing game scores, initiating a multiplayer game or chat, and more.

Face recognition lets you unlock your phone with your face.

Face Unlock

Android 4.0 introduces a completely new approach to securing a device, making each person's device even more personal — Face Unlock is a new screen-lock option that lets users unlock their devices with their faces. It takes advantage of the device front-facing camera and state-of-the-art facial recognition technology to register a face during setup and then to recognize it again when unlocking the device. Users just hold their devices in front of their faces to unlock, or use a backup PIN or pattern.

Wi-Fi Direct and Bluetooth HDP

Support for Wi-Fi Direct lets users connect directly to nearby peer devices over Wi-Fi, for more reliable, higher-speed communication. No internet connection or tethering is needed. Through third-party apps, users can connect to compatible devices to take advantage of new features such as instant sharing of files, photos, or other media; streaming video or audio from another device; or connecting to compatible printers or other devices.

Android 4.0 also introduces built-in support for connecting to Bluetooth Health Device Profile (HDP) devices. With support from third-party apps, users can connect to wireless medical devices and sensors in hospitals, fitness centers, homes, and elsewhere.

WIFI MECHANISM

                                                 WIFI MECHANISM

Wi-Fi or WiFi, is a mechanism that allows an electronic device to exchange data wirelessly over a computer network. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, tablet, or digital audio player, can connect to a network resource such as the Internet via a wireless network access point. An access point (or hotspot) has a range of about 20 meters (65 ft) indoors and a greater range outdoors. Hotspot coverage can comprise an area as small as a single room with walls that block radio signals or a large area, as much as many square miles, covered by multiple overlapping access points.
"Wi-Fi" is a trademark of the Wi-Fi Alliance and the brand name for products using the IEEE 802.11 family of standards. Only Wi-Fi products that complete Wi-Fi Alliance interoperability certification testing successfully may use the "Wi-Fi CERTIFIED" designation and trademark.
Wi-Fi has had a checkered security history. Its earliest encryption system, WEP, proved easy to break. Much higher quality protocols, WPA and WPA2, were added later. However, an optional feature added in 2007, called Wi-Fi Protected Setup (WPS), has a flaw that allows a remote attacker to recover the router's WPA or WPA2 password in a few hours on most implementations. Some manufacturers have recommended turning off the WPS feature. The Wi-Fi Alliance has since updated its test plan and certification program to ensure all newly-certified devices resist brute-force AP PIN attacks.


 Name WIFI
The term Wi-Fi suggests Wireless Fidelity, resembling the long-established audio-equipment classification term Hi-Fi (used since 1950) or high fidelity (in use since the 1930s). Even the Wi-Fi Alliance itself has often used the phrase Wireless Fidelity in its press releasesand documents; the term also appears in a white paper on Wi-Fi from ITAA.
The term Wi-Fi, first used commercially in August 1999, was coined by a brand-consulting firm called Interbrand Corporation that the Alliance had hired to determine a name that was "a little catchier than 'IEEE 802.11b Direct Sequence'". Belanger also stated that Interbrand invented Wi-Fi as a play on words with Hi-Fi, and also created the Wi-Fi logo.
The Wi-Fi Alliance initially used an advertising slogan for Wi-Fi, "The Standard for Wireless Fidelity", but later removed the phrase from their marketing. Despite this, some documents from the Alliance dated 2003 and 2004 still contain the term Wireless Fidelity. There was no official statement related to the dropping of the term.
The yin-yang Wi-Fi logo indicates the certification of a product for interoperability.
Non-Wi-Fi technologies intended for fixed points such as Motorola Canopy are usually described as fixed wireless. Alternative wireless technologies include mobile phone standards such as 2G, 3G or 4G



 
SYmbol For  WIFI .