Are you sick of sitting slack-jawed when the conversation turns to mobile tech? We know not everyone understands the techy stuff, so we’ve put together a jargon buster to help you understand the terms you might not be familiar with.

Your monthly bill

O2 Refresh

Our Pay Monthly plan where your bill is split into two parts – a Device Plan and an Airtime Plan. With O2 Refresh, you can upgrade your phone whenever you like. If you took out a contract before 17 December 2021, you’ll need to settle any outstanding amount on your Device Plan. If you took out a contract after 17 December 2021 and you’re over 24 months into your Device Plan, you can either continue paying your Device Plan instalments, or settle the outstanding amount.

Airtime Plan

Part of the O2 Refresh tariff, this is the monthly cost of your data, texts and minutes. It’s a 30-day rolling Airtime Plan, which means that, if you do decide to upgrade early there are no Early Termination Charges.

Device Plan

Part of the O2 Refresh tariff, this is the monthly cost of your device. When you pay off your Device Plan, you can upgrade to a new phone or tablet. If you took out a contract before 17 December 2021, you’ll need to settle any outstanding amount on your Device Plan, if you want to leave or upgrade. If you took out a contract after 17 December 2021 and you’re over 24 months into your Device Plan, you can either continue paying your Device Plan instalments, or pay off the remaining amount on your Device Plan, if you want to leave or upgrade.


The Retail Price Index (RPI) is a measure of the annual rate of inflation. We use it as a guide as to whether we adjust prices, as well as by how much. RPI can impact your Pay Monthly tariffs, including your O2 Refresh Airtime Plan (but not the Device Plan) and sim only tariffs. Find out more about RPI.


Operating system

An operating system used to power most phones and tablets that Apple doesn’t produce. Google maintains it, and there are a few different versions.

Fun fact: These versions used to be named after a tasty dessert: Ice Cream Sandwich, Marshmallow, and Oreo. However, in 2019, Google introduced a more traditional naming convention: Android 10, Android 11, and Android 12.


An operating system, used to power many smartphones and tablets. It's maintained by Google, and there are a few different versions.


An operating system developed by Apple, used to power iPads and iPhones.


WatchOS is the operating system for the Apple Watch. It shares many of the features of iOS, which runs the iPhone.

Windows Phone

Developed by Microsoft, Windows Phone is an operating system used to power smartphones and tablets. It’s the successor to Windows Mobile, and has two versions – Windows Phone 7 and Windows Phone 8.

App store

The Apple App Store allows iPhone users to download applications, like games and other useful tools. More generally, people often use the term ‘app store’ to refer to any shop on a mobile phone where you can download applications, such as Samsung’s Galaxy Store and the Google Play Store.


The terms processor and CPU can be used interchangeably. CPU stands for the central processing unit. It’s the part of a Smartphone that carries out your commands – processing your taps into actions.


A way of making video calls on Apple devices.

Google Play Store

The Google Play Store is where you download apps and games on Android phones.

Going online and our network


Second generation mobile network known as GSM. Simply put, 2G allows you to send text messages.


The third generation of mobile phone technology, offering better coverage for voice calls and text messaging, as well as providing faster access to the internet than our 2G network. All our tariffs come with 3G as standard until we switch off 3G services in 2025.  

H+ / HSPA+ / 3G.5

HSPA+ (shortened to H+ on phone screens) is a system for transferring information through third-generation mobile networks. It offers a faster internet connection than 3G – sometimes referred to as 3.5G.

Fun fact: It’s still a common network that your phone will connect to if 5G and 4G aren’t available.


The fourth generation of mobile phone technology. With 4G, using the internet on your phone is even quicker, with speeds 5-7 times faster than 3G. If you have a 4G ready phone, but you’re not in a 4G area, you’ll still be able to use 3G.


The fifth and latest generation of mobile phone technology, with connectivity that will completely transform the way we live. Get a better and more reliable connection in busy places, delay-free downloads and buffer-free streaming.

Cellular network

The radio network used to send and receive calls and messages, and use the internet.

O2 Wifi

A fast, free wifi service available to everyone. You just download the app, and you’ll be connected to O2 Wifi whenever you’re in a hotspot.


You can connect to the internet using wifi, to browse the web, download applications, or send and receive emails, without using your 3G or 4G data.

O2 Pocket Hotspot

A portable gadget that connects you and up to four other people or devices to the internet, when there’s O2 mobile data coverage. The O2 Pocket Hotspot automatically connects to our mobile network as soon as you insert a Pay As You Go sim.


A small USB device that allows you to access the internet with a 3G or 4G mobile broadband connection.


A program that you use to view websites. Safari, Internet Explorer, Firefox and Google Chrome are all examples of web browsers.


A mobile hotspot is a mini, personal wifi source you can easily create using your phone. A wifi hotspot uses mobile coverage, like 4G, and bounces it onto another device, like a laptop.


LTE, which stands for Long Term Evolution, is the technology behind 4G mobile networks. It gives you a high-speed connection to the internet while you’re on the move, making it possible to stream movies and TV.


Roaming happens when you use your phone in another country – the phone ‘roams’ onto a local network provider. Find out more about using your phone abroad.


SIM (subscriber identity module) cards connect you to a particular network. They come in three sizes, SIM, micro SIM and nano SIM, with most new phones using the smallest: nano size. SIM cards even have a small amount of storage capacity, letting you save a few contact details of friends and family.

Fun fact: If your SIM card becomes damaged, you can order a replacement and keep your phone number, as we can reprogramme a new SIM to take your number.

Taking pictures on a device

Superfast auto-focus

Superfast auto-focus lets you take movement and action shots, without the pictures becoming blurred. You can use superfast auto-focus on Samsung phones.

Quickshot camera

The quickshot camera lets you take photos almost instantly, even when your phone’s locked.

Panoramic shots

A photo specifically shot to include a wide landscape. It can also be used to get a 360 degree view, into one single photo. Many new smartphones include a panoramic shot feature.

Optical image stabilization

A technology used to produce clear photos and videos, without the blurriness caused by movement.

Digital zoom

Digital zoom refers to how much a camera can magnify a scene by cropping an image and making the remaining pixels larger. It’s shown as a number followed by an ‘x’, e.g., 3x (three times) digital zoom.

Fun fact: Phones don’t have space for many moving lenses like traditional cameras, so they often rely on digital zoom. The photo's clarity will suffer if you zoom in too much using digital techniques.

LED (flash)

LED stands for Light Emitting Diode. LEDs are like tiny light bulbs that use little power to produce a bright light. That makes them ideal for the camera flashes on phones.

Optical zoom

Optical zoom refers to how much a camera can magnify a scene without reducing the resolution of the final image. It works by changing the arrangement of the camera lenses to zoom in on a part of the scene, like a telescope. Digital zoom, on the other hand, zooms in on a section of the scene by cropping the image, meaning you get a smaller photo.

Screen information


The display that allows you to control and navigate through your phone by touching the screen with one or more fingers.

Fingerprint recognition

Technology that lets you unlock your phone using your fingerprints. It can also be used for payment via PayPal. To register a print, you need to swipe your finger eight times. This helps keep it secure.


A megapixel is one million pixels, and is a term used for the number of pixels in an image. Simply put, the higher the megapixel, the better the picture quality.


The aperture is the section of a phone’s camera that lets in light. It’s measured in f-stops, which are written as numbers such as f/1.8 or f/2.2. Smaller numbers indicate a wider opening, which gives a brighter image.

Fun fact: In ‘Pro’ camera modes, you can often change the aperture to make photos brighter or darker.


Resolution refers to the quality of an image, whether it’s a photo, video or the screen itself. It is measured in the number of pixels displayed along the horizontal and vertical lines. It is usually quoted as width x height – 1024 x 768 means the width is 1024 pixels and the height is 768 pixels.


AMOLED (Active Matrix Organic Light Emitting Diodes) is a display used in mobile phones originally popularised by Samsung. Most of the top smartphones now use it, as AMOLED can produce a wide range of colours and has a high ‘refresh rate’, which means you get a better picture for games and movies.

Fun fact: AMOLED screens are so thin that they don’t need a backlight. This can help save battery power.


A version of AMOLED that uses less power, is thinner and reflects less light. The layer of the screen that detects touch is built into the screen, rather than on top of it. According to Samsung, Super AMOLED reflects one-fifth as much sunlight as standard AMOLED, making it better to use outside.

Triluminos display

Technology that allows your phone or tablet to display a wider range of colours, to give you more vivid images.

Retina display

A display, on certain Apple devices, where the user is unable to make out the individual pixels of an image.

PPI/Pixel density

Pixel density is measured in pixels per inch (PPI) and is a way of checking screen quality in smartphones. The higher the pixel density, the clearer the images on your screen.


This is a full-HD display, with a higher pixel density to give you sharper and clearer images.


HD stands for high definition and is a screen resolution of 720 pixels by 1280 pixels, which is higher than a standard display. As phone screens are small, HD creates a clear image.

FHD / Full HD

Full HD, or FHD, means Full High Definition and is a resolution of 1920 pixels by 1080 pixels. It’s common on TVs but has also made its way to phone screens, offering a crystal-clear image. It’s also a common resolution for recording videos on phone cameras.

Hz (Hertz)

Hertz – abbreviated to Hz – is a unit of measurement that shows how quickly something changes. In mobile phones, it usually refers to the screen’s refresh rate. A 90Hz screen will refresh 90 times per second, making movement in videos, games, or scrolling look smooth.

Fun fact: 120Hz is currently considered the quickest commercially available refresh rate.


LCD stands for Liquid Crystal Display. It’s been a standard screen technology for a long time, making it cheaper to produce and more reliable. You’ll find LCD screens on many smartphones.

PPI (pixels per inch)

This one’s not about your payment protection insurance; it’s actually a measure of screen resolution. Pixels per inch tells you how many pixels are in every square inch of your phone screen. The higher the PPI, the sharper the image should appear on your screen.

Retina display

Retina Display is a brand created by Apple for their iPhones, iPads and MacBooks. A Retina Display has a high enough resolution to look like real life when looked at from an average distance.

Using data and device memory

Mobile data

Whenever you use the internet on your phone, you're using data. Whether it's browsing the web, sending an email, or watching a TV programme. Downloading and using apps also uses data.


Kilobits per second – a measure of how fast you can download online.


Megabits per second. Used when talking about broadband speeds. A Megabit is a measure of the data transfer rate, and is a million bits. A bit is the smallest unit of information in computing.

Data allowance

The amount of data usage that’s included in your tariff. Once you exceed this your data will be stopped until your allowance starts again. You'll still be able to connect to the internet using wifi.

Data cap

When you buy a 30 day mobile broadband package from us, you get 30 days to use the data before it expires. If you top up within that 30 days, we’ll roll over any leftover data.


Measured in GB (gigabytes), this tells you how much data such as videos, photos and music your phone can hold. If you’re someone who takes a lot of photos, downloads lots of apps and stores lots of music then you’ll need to have more memory on your phone.


An SD Card (Secure Digital Card) is a small, external memory. Some mobile phones have a slot to enter an SD Card in order to increase the amount of storage on the phone.


To transfer a file from the internet to your phone. For example, when you buy an app, you download it from the app store, onto your phone.


To transfer a file or files from your phone to the internet. For example, when you transfer a photo from your phone to Facebook, it’s called uploading.


Short message service. You probably know it as text messaging. SMS messages are restricted to 160 characters.


Multimedia Messaging Service (MMS) is a way to send messages that include multimedia content, including picture messages, to and from mobile phones.

Data storage

Data storage can refer to the memory in your phone, i.e. the amount of space available for apps, photos, etc, or the memory in a cloud storage service such as iCloud or Google Drive.

Gigabyte (GB)

A gigabyte is a unit of measure for digital data. A gigabyte is 1,000,000,000, and a byte can store a single typed letter. Gigabytes refer to the amount of data you can download each month as part of a mobile phone contract, usually ranging from 1GB to 100GB.

Fun fact: Gigabytes are also the measure used for your phone’s storage capacity. Storage capacities can range from 2GB for simple phones to over 1 terabyte (1,000GB) for the most powerful new phones. Most phones have either 32GB, 64GB or 128GB of storage.


RAM, or Random Access Memory, is your phone’s short-term memory. It’s used by open applications, letting them remember what’s just happened to keep things running smoothly. A high amount of RAM lets you run more applications at once or more complex applications.

O2 apps and other info


Short for application. Apps are software you can use on your smartphone.


The Priority O2 app gives you discounts at stores, restaurants, cinemas, and more, as well as the opportunity to buy gig and event tickets 48 hours before general release.

O2 Recycle

You can trade in your old phone or tablet for cash with O2 Recycle. You get a great price for your handset, and it’s good for the environment.

O2 Tech Experts

O2 Tech Experts offer free and friendly advice on anything from your phone, to your mobile broadband or laptop. You can find them online, in many of our shops, or over the phone. 

General info

SAR rating

Specific absorption rate - a measurement of how much radiation is absorbed by the body while using a mobile phone. The higher the SAR the more radiation is absorbed so, if you’re concerned about this, choose a phone with a low SAR rating.

Eco rating

When a new phone is produced, we work with the manufacturers rate its sustainability between 0 and 5. The higher the rating the more sustainable the phone is.


A multi-band device (including dual-band, tri-band, quad-band and penta-band devices) is a mobile phone that supports roaming, so you’re able to use your phone abroad.


GPRS stands for General Packet Radio Services. It’s a system for transferring information over mobile networks, allowing a connection to the internet.

Fun fact: It was introduced as part of the second generation of mobile networks and is an integral part of 3G networks.


Edge (Enhanced Data for GSM Evolution), or 2.75G, provides faster data rates than GPRS.


The Global Positioning System is a satellite navigation system that provides location and time information in all weather conditions. The GPS on your phone can find your location, and give you directions to your destination.


The Global System for Mobiles, is the agreed standard for mobile networks.


GPU stands for Graphics Processing Unit. It’s a specialist part of a mobile phone or computer that turns electrical signals into images on the screen. Powerful GPUs are essential for gaming, where the images on the screen change often and unpredictably as you interact with the game.


A way of exchanging data wirelessly, over short distances. It’s commonly used for connecting your phone to your car, or a headset, so you can use your phone ‘hands free’.

Fun fact: Bluetooth is named after a 10th-century Danish king who unified Denmark and Norway. He connected Nordic people, so he was believed to be a good inspiration for connective technology. The Bluetooth symbol, an angular ‘b’, is a blend of the ancient Danish runes that correspond to ‘b’ and ‘t’.


A clamshell is a type of phone that folds in half. They were common in the 1990s and early 2000s as people wanted smaller and smaller phones. The most famous is the Motorola Razr.

Fun fact: With the recent development of flexible touchscreens, clamshell phones are coming back with the likes of the Samsung Galaxy Z Flip3 and Samsung Galaxy Z Flip4

Flight mode

This is a setting available on most mobile phones. It turns off your phone’s mobile network connection, disabling calls, texts, and connection to the internet.

Fun fact: This mode’s purpose is to ensure your phone doesn’t interfere with any of the instruments on a plane when flying.


Instant messaging is a type of online chat. It’s just like text messaging, except it’s done over the internet.


A unique number given to every single mobile phone. It’s usually found behind the battery.


The names and phone numbers you have stored on your phone or sim.

PUK code

The PUK (Personal Unblocking Key) code is an eight-digital number used to unblock your SIM card. Find out more about unblocking your phone.


The PAC (Port Authorisation Code) combines letters and numbers that lets you move your mobile number from one provider to another.


NFC stands for Near Field Communication. It’s very short-range communication technology, working over a few centimetres. In smartphones, it’s most commonly used to make secure payments in the same way you do with a contactless bank card.

Fun fact: It can also be used to send data to another phone with NFC. That’s particularly useful when setting up a new phone, as simply touching the phones together can transfer your data.


Biometrics are your unique biological data. It usually refers to your fingerprints, which you can use to unlock many newer phones. It would also include images of your face used for facial recognition.


Emojis are simple pictures you can include in text messages to help brighten conversations and convey more meaning. They’re called emojis because they started as pictures of faces showing different emotions, such as a smile or frown. Now there are emojis for all sorts of things, from animals to the zodiac.


One MHz (megahertz) represents one million cycles per second. The microprocessor that powers your phone is measured in megahertz. The higher the MHz, the quicker your phone.

Lightning cable/port

Apple developed the Lightning connection for the iPhone. iPhones have a Lightning port on the bottom that you can plug a Lightning cable into to charge the phone or transfer data to another device.

Fun fact: The clever thing about Lightning is that it’s reversible. There isn’t a ‘right way up’ when plugging in the cable, making it much less fiddly than traditional USB-A connections.

Soft keys

Soft keys are the buttons or keyboards on touchscreens. They can also be physical buttons on your smartphone that do different things based on the context. For example, many Samsung smartphones have a physical Bixby key on the side. You can reprogramme that key in the settings, making it a soft key.

T9 keys

T9 stands for text on nine buttons, so T9 keys are the buttons you see on non-touchscreen phones, where the letters of the alphabet are spread across the number keys.

USB Type-C

USB Type-C is the latest generation of physical computer connection, letting you connect your mobile phone to other devices through a USB-C cable. It’s small enough to be used across mobile phones and laptop computers and is reversible, so it doesn’t matter which way up you plug it in.


Zeiss is a premium camera lens brand that’s come to smartphones in recent years. While there are no unique features of a Zeiss lens, the name is a sign of quality that should give you confidence in the ability of your camera phone.

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