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A SIM identifies a subscriber for network access; an IMEI identifies the handset. That distinction is a useful starting point for understanding the terms you may see in phone settings, carrier materials, or wireless news. This glossary explains common mobile-phone and network vocabulary in plain language. Phone-category labels and network-generation names are broad terms, not guarantees of a particular feature set or connection speed.
Phone types
Basic phone, feature phone, and smartphone are useful shorthand, but they are not rigid technical classes. The International Telecommunication Union’s 2017 report on mobile handsets notes that the boundaries between these categories have blurred. The descriptions below are general tendencies, not rules for every model.
| Term | General meaning |
|---|---|
| Basic phone | A phone with a limited set of functions and little or no data connectivity. The description reflects broad tendencies in the ITU’s 2017 report, not a current universal classification. |
| Feature phone | A middle category between basic phones and smartphones: it generally has more functions than a basic phone, but limited functionality and often a proprietary operating system. The boundaries vary by market and have blurred over time. |
| Smartphone | A phone in the broadest-function category, typically built to run apps and use data services. The ITU report discusses this category alongside basic and feature phones, while noting that their distinctions have become less clear. |
These are category descriptions, not a checklist that determines whether a specific handset qualifies. The source is a 2017 ITU report, not a survey of today’s phone market. ITU-T, “Mobile Handset Use in Digital Financial Services”
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Network generations and related organizations
Generation labels indicate a broad era of mobile-network technology. An abbreviation’s expansion can help decode a label, but does not by itself specify a full technical standard or promise a particular user experience.
#1 Best Overall
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Samsung Galaxy A17 5G Smart Phone 128GB US 1 Yr Manufacturer Warranty Black
- YOUR CONTENT, SUPER SMOOTH: The ultra-clear 6.7" FHD+ Super AMOLED display of Galaxy A17 5G helps bring your content to life, whether you're scrolling through recipes or video chatting with loved ones.¹
- LIVE FAST. CHARGE FASTER: Focus more on the moment and less on your battery percentage with Galaxy A17 5G. Super Fast Charging powers up your battery so you can get back to life sooner.²
- MEMORIES MADE PICTURE PERFECT: Capture every angle in stunning clarity, from wide family photos to close-ups of friends, with the triple-lens camera on Galaxy A17 5G.
- NEED MORE STORAGE? WE HAVE YOU COVERED: With an improved 2TB of expandable storage, Galaxy A17 5G makes it easy to keep cherished photos, videos and important files readily accessible whenever you need them.³
- BUILT TO LAST: With an improved IP54 rating, Galaxy A17 5G is even more durable than before.⁴ It’s built to resist splashes and dust and comes with a stronger yet slimmer Gorilla Glass Victus front and Glass Fiber Reinforced Polymer back.
- 2G: Second Generation Mobile. A label for second-generation mobile technology.
- 3G: Third Generation Mobile. A label for third-generation mobile technology.
- 4G: Fourth Generation Mobile. A label for fourth-generation mobile technology; it is not a promise of a fixed connection speed.
- LTE: Long Term Evolution. A mobile-network technology name commonly seen in phone network indicators. The expansion alone does not specify speed or performance.
- GPRS: General Packet Radio Service. An acronym associated with mobile packet-data service.
- GSM: Global System for Mobile Communications. The expansion of a mobile-communications standard’s name.
- HSPA: High Speed Packet Access. The expansion of a mobile-network technology acronym.
- 3GPP: Third Generation Partnership Project. The name of the partnership behind mobile telecommunications specifications.
Actual performance depends on the network, device, location, and service conditions; the sources cited here do not establish a speed for any generation or technology. For official vocabulary related to International Mobile Telecommunications, ITU-R Recommendation M.1224-1 is listed as in force on the ITU page and was approved on 15 March 2012. ITU-R Recommendation M.1224-1
Subscriber and device identifiers
SIM, IMSI, and IMEI refer to different parts of a mobile connection. A subscriber identity is not the same as the identity of the physical device.
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Motorola Moto G Play LTE | Unlocked | Made for US 4/64GB | 50MP Camera | Sapphire Blue
- Blazing-fast Qualcomm performance. Get the speed you need for great entertainment with a Snapdragon 680 processor and 4GB**** of RAM.
- Fluid display + immersive stereo sound. Bring your entertainment to life with an ultrawide 6.5" 90Hz* HD+ display plus stereo speakers, Dolby Atmos, and Hi-Res Audio**.
- 50MP*** Quad Pixel camera. Capture sharper, more vibrant photos day or night with 4x the light sensitivity.
- 64GB**** built-in storage. Get plenty of room for photos, movies, songs, and apps—and add up to 1TB more with a microSD card*****.
- Unbelievable battery life. Work and play nonstop with a long-lasting 5000mAh battery.*****
- SIM: Subscriber identity module. A SIM is associated with subscriber identity and network access. In devices that use a removable SIM card, it can be moved to another compatible device; not every phone uses the same physical SIM arrangement. CTIA describes a SIM card as communicating with a wireless network using a unique code. CTIA, “Today’s Mobile: Cybersecurity—Protected, Secured and Unified”
- IMSI: International Mobile Subscriber Identity. This term refers to a subscriber identity, rather than the identity of the handset.
- IMEI: International Mobile Equipment Identity. A unique number associated with a mobile device and used within a wireless network to identify it. The IMEI is not the SIM, and having an IMEI alone does not establish whether a device is eligible for service. CTIA, “Today’s Mobile: Cybersecurity—Protected, Secured and Unified”
- EIR: Equipment identity register. In ITU-T terminology, a network element that performs checks involving IMEI status. ITU-T Q Supplement 76 (10/2023)
Carriers and network access
- MNO: Mobile network operator. Broadly, a company that operates a mobile network and provides network service. CTIA’s glossary defines the term in a U.S. context as a provider licensed by the Federal Communications Commission to deploy and operate commercial mobile networks; that regulatory wording is not a global definition.
- MVNO: Mobile virtual network operator. A company that buys network capacity from an operator and sells service under its own brand, sometimes with added services. CTIA’s explanation comes from an older U.S.-framed industry glossary, so local arrangements and regulatory meanings can differ.
- RAN: Radio access network. The part of a mobile network that connects devices over radio to the wider network. CTIA includes this consumer-facing term in its glossary. CTIA, “Today’s Mobile: Cybersecurity—Protected, Secured and Unified”
Messaging, short-range connection, and older web terms
- SMS: Short Message Service. The standard expansion for text messaging.
- USSD: Unstructured Supplementary Service Data. A mobile-network service term, often encountered in the context of codes entered on a phone to access a service.
- NFC: Near Field Communication. Short-range wireless communication between nearby devices or objects.
- WAP: Wireless Application Protocol. A protocol name associated with early mobile web services; it is useful to recognize in older materials.
These expansions come from the abbreviation list in the ITU-T handset report. They are entry points for understanding the terms, not complete technical specifications or claims about current availability. ITU-T, “Mobile Handset Use in Digital Financial Services”
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Bestseller No. 4
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BLU G35 | 2025 | Unlocked | 6.5” HD+ Infinity Display | Dual 8MP Camera + LED Flash 5MP Selfie Camera | 32GB/3GB I US Version | US Warranty | Grey
- GSM Unlocked: Enjoy seamless connectivity with your preferred GSM carrier. Compatible with T-Mobile, Metro PCS, AT&T, Cricket, Mint Mobile and other GSM networks. SIM card not included. For network compatibility, please check with your carrier. Note: Not compatible with CDMA networks like Verizon (Visible, Spectrum Mobile, US Mobile, Total Wireless, Straight Talk Wireless)
- Boundless Views: Enjoy immersive viewing on the spacious 6.5” HD+ display. Whether you're watching videos, browsing, or gaming, every detail comes through with stunning clarity.
- Smooth Performance, All Day: Powered by an efficient octa-core processor, the G35 ensures smooth performance for your everyday tasks. Enjoy faster app launches, seamless multitasking, and reliable speed.
- Snap, Share, Repeat: The G35 features a dual rear camera setup for sharp, detailed shots, and a front-facing camera that’s perfect for selfies and video calls. Capture every moment with ease and clarity.
- Effortless Access: Keep your phone secure with A.I. Face ID technology. Instantly unlock your G35 with just a glance. It's fast, easy, and secure.
Rank #4
SAMSUNG Galaxy A16 4G LTE (128GB + 4GB) International Model SM-A165F/DS Factory Unlocked 6.7" Dual Sim 50MP Dual Cam (Case Bundle) (Gray)
- Please note, this device does not support E-SIM; This 4G model is compatible with all GSM networks worldwide outside of the U.S. In the US, ONLY compatible with T-Mobile and their MVNO's (Metro and Standup). It will NOT work with Verizon, Spectrum, AT&T, Total Wireless, other CDMA carriers, it is also not compatible with their MVNO (Visible, Xfinity Mobile, US Mobile, Cricket Wireless, etc).
- Compatibility with certain third-party devices and accessibility accessories, including some hearing aids, may vary depending on manufacturer support, Bluetooth protocols, software compatibility, and regional firmware limitations. For additional hearing aid compatibility information, please refer to Samsung’s official support documentation.
- 4G LTE Bands: B1/B3/B5/B7/B8/B20/B28/B38/B40/B41
- Display: Super AMOLED, 90Hz, 800 nits (HBM) | 6.7 inches, 110.2 cm2 (~86.0% screen-to-body ratio) | 1080 x 2340 pixels, 19.5:9 ratio (~385 ppi density)
- Camera: 50 MP, f/1.8, (wide), 1/2.76", 0.64µm, AF | 50 MP, f/1.8, (wide), 1/2.76", 0.64µm, AF | 2 MP, f/2.4, (macro)
Rank #3
Samsung Galaxy A16 4G LTE (128GB + 4GB) International Model SM-A165F/DS Factory Unlocked, 6.7", Dual SIM, 50MP Triple Camera (Case Bundle), Black
- Please note, this device does not support E-SIM; This 4G model is compatible with all GSM networks worldwide outside of the U.S. In the US, ONLY compatible with T-Mobile and their MVNO's (Metro and Standup). It will NOT work with other CDMA carriers, and it is also not compatible with their MVNO (Visible, Xfinity Mobile, US Mobile, Cricket Wireless, etc).
- Compatibility with certain third-party devices and accessibility accessories, including some hearing aids, may vary depending on manufacturer support, Bluetooth protocols, software compatibility, and regional firmware limitations. For additional hearing aid compatibility information, please refer to Samsung’s official support documentation.
- Camera: 50 MP, f/1.8, (wide), 1/2.76", 0.64µm, AF | 50 MP, f/1.8, (wide), 1/2.76", 0.64µm, AF | 2 MP, f/2.4, (macro). Battery: 5000 mAh, non-removable | A power adapter is NOT included.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
