2G

Second-generation, circuit-switched, digital wireless technology that offers better quality over the first-generation analog wireless technology and introduces data capabilities. The two primary 2G technologies offered by wireless service providers today are CDMA and GSM . First generation focused primarily on voice communications while 2G networks still focus on voice but also introduce limited data capabilities. 2G data rates are in the 9 kbit/s range.

2.5G

2.5G introduces enhanced data capabilities and was designed to bridge the gap between the 2G and the full-fledged deployment of 3G . CDMA 1xRTT represents the 2.5G step for the wireless service providers that offer CDMA , while GPRS / EDGE represents the 2.5G step for the wireless service providers that offer GSM . Typical 2.5G data rates are in the 56kbit/s to 144 kbit/s range. Unless in an ideal location, actual results will more typically be in the 25 kbit/s – 60 kbit/s range.

3G

Third generation digital wireless technology that while offering superior voice quality and higher network capacity, moves away from voice-centric services to Internet Protocol (IP)-based services that approach broadband data rates. The 3G solution for CDMA wireless service providers is 1xEVDO . UMTS / HSDPA represents the 3G solution for GSM wireless service providers. Typical 3G data rates are in the 144 kbit/s to 2.4 mbit/s.

CDMA

Code Division Multiple Access (CDMA) is a spread spectrum technology that allows many users to occupy a pair (uplink/downlink) of 1.25Mhz channels. Unique codes differentiate users in the same channel. The first iteration of CDMA was IS-95A, which supports a circuit-switched data rate of 14.4 kbit/s. IS-95B supports data rates up to 64 kbit/s by aggregating channels. CDMA as a whole is generally considered 2G technology though some designate IS-95B as 2.5G .

1X-RTT

CDMA 1xRTT, one times Radio Transmission Technology, operates in the spectrum of one pair (uplink / downlink) of CDMA channels. Data rates up to 144 kbit/s are supported, with typical rates around 60 kbits/s, with better voice quality and higher network capacity. Though typically considered the CDMA solution for 2.5G , some consider 1xRTT a 3G technology.

1xEVDO

EVDO once meant Ev olution D ata O nly but has now come to be an acronym for Ev olution D ata O ptimized. With data rates up to 2.4 mbits/s, this represents the CDMA solution for 3G . 1xEVDO is the evolution of CDMA 1xRTT and only supports data transfers.

GSM

G lobal S ystem for M obile communications is a 2G digital wireless technology. GSM separates user firstly by 200 KHz channels, and then via time slots within the channel. Each channel has 8 time slots and can thus support up to 8 voice calls per channel.

GPRS

G eneral P acket R adio S ervice is a packet-switched data technology with data rates up to 115 kbits/s, and typically 40 to 50 kbits/s. GPRS that represents the GSM solution for 2.5G .

EDGE

E nhanced D ata G SM E nvironment is an evolution of GPRS , providing high-speed data services up to 384 kbits/s on GSM networks.

HSDPA

H igh- S peed D ownlink P acket A ccess is an improvement of UMTS , the GSM answer to 3G . HSDPA will support theoretical peak speeds up to 14.4 mbits/s with typical rates in the 400 kbits/s to 600 kbits/s range.

UMTS

U niversal M obile T elecommunications S ystem is the GSM answer for 3G . It is based on wideband, 5 Mhz, CDMA channels, also called WCDMA. UMTS supports voice, data and video services with stationary data rates up to 2 mbit/s and mobile data rates up to 384 kbits/s.

WiMAX

W orldwide I nteroperability for M icrowave A ccess is based on the IEEE 802.16 family of standards. There are two, incompatible, versions of WiMAX.

802.16d WiMAX only supports fixed access; also referred to as 802.16-2004.

802.16e WiMAX supports mobile and fixed access; also referred to as 802.16-2005 or Mobile WiMAX.

WiFi

Wi reless Fi delity is based on the 802.11 family of standards. The most common versions in use are 802.11 b,a, and g.

802.11b transmits at a frequency of 2.4 GHz with data rates up to 11 Mbps using Complementary Code Keying modulation [CCK]. IEEE802.11b was released in 1999. The 802.11b standard was rendered obsolete with the introduction of 802.11g in 2003. There are very few Wireless-B products offered any longer due to fact that Wireless-g equipment operates at a much higher speed and over a greater distance [at the higher speeds]. IEEE 802.11b and 802.11g are compatible so devices can coexist in the same network.

802.11a transmits at a frequency of 5 GHz with data rates of 54 Mbps using Orthogonal Frequency Division Multiplexing [ OFDM ].

802.11g transmits at a frequency of 2.4 GHz with data rates of 54Mbps [OFDM, DSSS]. IEEE 802.11b and 802.11g are compatible, devices can coexist in the same network.

PCS

Refers to wireless technologies (e.g. CDMA or GSM) that operate in the 1900 MHz band (North America, South America, Asia and Pacific Islands ) or the 1800 MHz (most of the rest of the world).

Cellular

Refers to wireless technologies (e.g. CDMA or GSM) that operate in the 850 MHz band (North America, South America ) or the 900 MHz (most of the rest of the world).

Bluetooth

A low-cost, short range (30 feet) radio link between laptops, mobile phones, head sets, network access points and other devices. Bluetooth can replace cables and is to today supported by a wide range of devices.

Band

The band(s) for a device refers to the frequency range(s) that it transmits and receives on.

Marketing blurbs referring to a device as being dual mode, dual-band, tri-mode, or quad-band has some typical meanings but in reality is all quite ambiguous. It is important to focus on the actual frequencies and air interface technologies that a particular device supports. In North America, the 1900 MHz (PCS) and 850 (cellular) MHz frequency bands are available to service providers. On most other continents, 900 MHz is used for cellular and 1800 MHz is used for PCS. 2100 MHz has been allocated for high speed data in parts of Africa, Asia and Europe.

Digital Dual-Band

A CDMA dual-band mobile device almost always refer to a phone that will operate on both the 1900 MHz (PCS) and 850 MHz (cellular) frequency bands. A dual-band GSM device sold in North America is today rather rare, but refers to a device that supports any two of the four GSM frequency bands. More commonly, GSM devices will have tri-band or quad-band capabilities. 

Digital Tri-Band

Tri-band mobile devices usually supporting the 850/1800/1900 bands or the 900/1800/1900 bands. The former provides good coverage in North America whereas for the later, only the 1900 band is supported in North America. UMTS tri-band or equivalently HSDPA/UMTS tri-band refers to high-speed data over the 850/1900 and the relatively recently designated 2100 MHz frequency band for Africa, Europe and parts of Asia.

Digital Quad-Band

Quad-band mobile devices typically refer to devices that support the GSM 850/900/1800/1900 band of frequencies but in recent times have also come to refer to the 900/1800/1900/2100 band of frequencies supporting high speed data. Only the 1900 MHz band from this later set is supported in North America.

Dual Mode

Dual-mode for both CDMA and GSM usually imply support for analog but in recent times has also come to refer to devices that support Wi-Fi and either CDMA or GSM.

Tri-Mode

A tri-mode phone is typically used to describe a CDMA phone that supports analog (also referred to as AMPS) 850, CDMA cellular (850) and CDMA PCS (1900). Tri-mode has also been used to refer to devices that support AMPS, CDMA and Globalstar satellite.

PC Card

The PC Card is a credit card-size peripheral that adds memory, mass storage, and I/O capabilities to computers with an interface that utilizes a connection to ISA-style (16-bit interface) or PCI (32-bit CardBus interface) parallel busses. When the PC Card uses the CardBus interface in what is referred to as DWORD mode, a theoretical maximum of 132 mbytes / sec data transfer can be achieved. The actual rate may be significantly less than this. If using what is referred to as byte mode, the theoretical maximum is 33 mbytes /sec. PC Cards come in 3 types conveniently referred to Type I, Type II, and Type III with the primary difference being in the thickness of the card. Type I cards are typically used for memory (SRAM, flash, etc). Type II cards are typically used for I/O devices such as cellular modems and Wi-Fi cards. Type III PC Cards are typically used for connecting rotating mass storage devices.

ExpressCard

The ExpressCard is relatively new and was developed to bring higher speed, greater flexibility and lower cost than the PC Card by utilizing a connection to the PCI Express or USB 2.0 interfaces. When the ExpressCard uses a PCI Express interface, then a theoretical maximum 2.5 Gbit/sec data rate can be achieved. When using a USB 2.0 interface, then a theoretical maximum 480 Mbit/sec can be achieved.

VGA

Video Graphics Array. A standard image representation of size of 640 x 480 pixels. This can refer to the size/resolution of a display, an image (file), or a camera.

QVGA

Quarter VGA has an image size of 320 x 240 pixels, or 1/4th the size of VGA. This can refer to the size/resolution of a display, an image (file), or a camera.

QWERTY

A standard layout for letter keys on text keyboards and thumboards. It is named for the order of the first six keys on the top row.