Query: The IPhone 4 is a type of telephone.

Relevant passages:
IPhone <=SEP=> 7 / 7 Plus :  -RCB- -RCB-  | unitssold = 1 billion +   | service =  -RCB- -RCB-  iPhone ( -LSB- ˈaɪfoʊn -RSB- ) is a line of smartphones designed and marketed by Apple Inc. . They run Apple 's iOS mobile operating system . The first generation iPhone was released on June 29 , 2007 , and there have been multiple new hardware iterations since .   The user interface is built around the device 's multi-touch screen , including a virtual keyboard . The iPhone has Wi-Fi and can connect to cellular networks . An iPhone can shoot video ( though this was not a standard feature until the iPhone 3GS ) , take photos , play music , send and receive email , browse the web , send and receive text messages , follow GPS navigation , record notes , perform mathematical calculations , and receive visual voicemail . Other functionality , such as video games , reference works , and social networking , can be enabled by downloading mobile apps . , Apple 's App Store contained more than 2.2 million applications available for the iPhone .   Apple has released ten generations of iPhone models , each accompanied by one of the ten major releases of the iOS operating system . The original 1st-generation iPhone was a GSM phone and established design precedents , such as a button placement that has persisted throughout all releases and a screen size maintained for the next four iterations . The iPhone 3G added 3G network support , and was followed by the 3GS with improved hardware , the 4 with a metal chassis , higher display resolution and front-facing camera , and the 4S with improved hardware and the voice assistant Siri . The iPhone 5 featured a taller , 4-inch display and Apple 's newly introduced Lightning connector . In 2013 , Apple released the 5S with improved hardware and a fingerprint reader , and the lower-cost 5C , a version of the 5 with colored plastic casings instead of metal . They were followed by the larger iPhone 6 , with models featuring 4.7 and 5.5-inch displays . The iPhone 6S was introduced the following year , which featured hardware upgrades and support for pressure-sensitive touch inputs , as well as the SE -- which featured hardware from the 6S but the smaller form factor of the 5S . In 2016 , Apple unveiled the iPhone 7 and 7 Plus , which add water resistance , improved system and graphics performance , a new rear dual-camera setup on the Plus model , and new color options , while removing the 3.5 mm headphone jack found on previous models .   The original iPhone was described as `` revolutionary '' and a `` game-changer '' for the mobile phone industry . Newer iterations have also garnered praise , and the iPhone 's success has been credited with helping to make Apple one of the world 's most valuable publicly-traded companies .

IPhone 4 <=SEP=> The iPhone 4 is a smartphone that was designed and marketed by Apple Inc. . Following a number of notable leaks , the iPhone 4 was first unveiled on June 7 , 2010 , at Apple 's Worldwide Developers Conference in San Francisco , and was released on June 24 , 2010 , in the United States , United Kingdom , France , Germany and Japan . It is the 4th generation of iPhone , succeeding the 3GS and preceding the 4S .   The iPhone 4 introduced a new hardware design to the iPhone family , which Apple 's CEO Steve Jobs touted as the thinnest smartphone in the world at the time ; it consisted of an uninsulated stainless steel frame which doubles as an antenna , with internal components situated between chemically strengthened aluminosilicate glass . The iPhone 4 also introduced Apple 's new high-resolution `` Retina Display '' ; while maintaining the same physical size and aspect ratio as its precursors , its liquid crystal display had a pixel density of 326 pixels per inch . The iPhone 4 also introduced Apple 's A4 system-on-chip , along with iOS 4 -- which notably introduced multitasking functionality and Apple 's new FaceTime video chat service . The iPhone 4 was also the first iPhone to include a front-facing camera , and the first to be released in a version for CDMA networks , ending AT&T 's period as the exclusive carrier of iPhone products in the United States .   It was succeeded as Apple 's flagship smartphone in 2011 by the iPhone 4S . However , iPhone 4 continued to be produced until 2013 .   The iPhone 4 received generally positive reception , with critics praising its revamped design and more powerful hardware in comparison to previous models . While it was a market success , with over 600,000 pre-orders within 24 hours , the release of the iPhone 4 was plagued by highly publicized reports that abnormalities in its new antenna design caused the device to lose its cellular signal if held in a certain way . Most human contact with the phone 's outer edge would cause a significant decrease in signal strength .   The iPhone 4 spent the longest time as Apple 's flagship iPhone model at fifteen months , and had the longest lifespan of any iPhone ever produced , spanning close to four years and available in some developing countries until early 2015 .

Smartphone <=SEP=> A smartphone is a mobile personal computer with an advanced mobile operating system with features useful for mobile or handheld use . Smartphones , which are typically pocket-sized ( as opposed to tablets , which are much larger in measurement ) , have the ability to place and receive voice/video calls and create and receive text messages , have personal digital assistants ( such as Siri , Google Assistant , Alexa , Cortana , or Bixby ) , an event calendar , a media player , video games , GPS navigation , digital camera and digital video camera . Smartphones can access the Internet through cellular or Wi-Fi and can run a variety of third-party software components ( `` apps '' from places like Google Play Store or Apple App Store ) . They typically have a color display with a graphical user interface that covers more than 76 % of the front surface . The display is almost always a touchscreen and sometimes additionally a touch-enabled keyboard like the Priv/Passport BlackBerrys , which enables the user to use a virtual keyboard to type words and numbers and press onscreen icons to activate `` app '' features .   In 1999 , the Japanese firm NTT DoCoMo released the first smartphones to achieve mass adoption within a country . Smartphones became widespread in the late 2000s . Most of those produced from 2012 onward have high-speed mobile broadband 4G LTE , motion sensors , and mobile payment features . In the third quarter of 2012 , one billion smartphones were in use worldwide . Global smartphone sales surpassed the sales figures for regular cell phones in early 2013 .