Dual-SIM – As a SIM links a phone to a specific carrier (service provider), billing account, and phone number, a dual-SIM phone can be linked to two different phone numbers associated with two different billing accounts. Those accounts and phone numbers can be with different carriers, and even in different countries.
One common use is to use one phone with both a business phone number (an account and a separate personal line. Another use is to have accounts with carriers in two different countries, in order to take advantage of favorable rates for local versus international calls, or to permit favorable rates for people calling you, by having local phone numbers in two countries.
GSM stands for Global System for Mobile Communication and is the most popular 2G mobile phone standard in the world.
GSM is used by about 80% of all mobile phones – approximately 2 billion people across more than 212 countries.
The widespread use of the GSM standard has made it easy for most mobile phone users to use their phones overseas thanks to roaming agreements between operators using the same GSM standard.
GSM – then labeled Groupe Spécial Mobile was originally conceived back in 1982 as a European standard for mobile phones. The first GSM network went live in 1992 in Finland.
GSM introduced the concept of the SIM card (Subscriber Identity Module card) – a detachable smart card that lets users swap their phone numbers and contacts between handset.
3G – Analog cellular phones were the first generation while digital marked the second generation. 3G is loosely defined, but generally includes high data speeds, always-on data access, and greater voice capacity.
The high data speeds are possibly the most prominent feature, and certainly the most hyped. They enable such advanced features as live, streaming video.
There are several different 3G technology standards. The most prevalent is UMTS, which is based on WCDMA (the terms WCDMA and UMTS are often used interchangeably).
MMS is an extension of the SMS (Short Message Service) protocol, allowing the exchange of text messages exceeding 160 characters. Unlike SMS, which is text-only, MMS can deliver a variety of media. This media may include up to forty seconds of video, audio, one image, or a slideshow of multiple images. MMS requires a third-generation (3G) network to send large MMS messages (though smaller MMS messages may be transmitted over second generation networks using GPRS).
Bluetooth is an industry-standard for contactless data transmission and communication between two devices. The range is usually 1 to 10 m and rarely more than 100 m. In some cases, distances of up to 200 m are possible.
The name of EDGE in full is Enhanced Data rates for GSM Evolution. This is a 2.75G technology further developed from the 2G and 2.5G technologies. Its data transmission speed is higher than that of GPRS and is closer to 3G technology.
Wi-Fi is a short-range wireless communication technology adopting the 802.11 wireless network standard. Most notebook computers, mobile phones, or mobile Internet devices nowadays are able to support Wi-Fi wireless connection. The transmission speed of Wi-Fi can be up to 54 Mbps, while its communication range can reach 305 meters with high stability and reliability. At present, many coffee shops, shopping malls, hotels, and airports offer chargeable or free-of-charge Wi-Fi wireless broadband. The service is also available on some public transport.
Universal Serial Bus. USB provides a single common interface to peripherals and plug-and-play configuration (at the host/pc).
USB was created in 1996 by a consortium of companies (let by Intel) with the aim of dramatically simplifying the connection of peripheral devices to a computer.
The original standard for USB (occasionally referred to as USB 1.0, but normally simply as USB) supported transfer speeds of 1.5Mbps and 12Mbps. USB 1.1 is a revised version of the USB specification, but the transfer rate remains unchanged. USB 2.0 (also referred to as “USB Hi-Speed) also supports 480Mbps and is otherwise backward compatible with earlier versions. The USB specification limits maximum cable lengths to 5m for high-speed USB devices and 3m to low-speed devices USB.
USB 3 significantly increased the possible maximum transfer rate but doubles the number of cables required internally to 8. The internal cables prior to USB 3 were for power, ground, and a pair for differential data. USB adds two more pairs of cables for (4 additional cables).
Universal Serial Bus (USB): A standard port that enables you to connect external devices (such as digital cameras, scanners, keyboards, and mice) to computers. The USB standard supports data transfer at three rates: low speed (1.5MBps), full-speed (12Mbps), and high speed (480 MBps).
Mbps=million bits per second.
HDMI – Stands for High-Definition Multimedia Interface. HDMI is a digital interface for transmitting audio and video data in a single cable. It is supported by most HDTVs and related components, such as DVD and Blu-ray players, cable boxes, and video game systems.