< Prev     Specialized Mobile Radio (SMR) Dispatch service ("walkie-talkie-type" service used by taxis, delivery trucks, etc.). SMR providers in the United States operate in the 800 MHz and 900 MHz frequency bands. Specific Absorption Rate (SAR) A measure of the rate at which RF energy is absorbed by the body. Spectrum Cap A limit to the allocated spectrum designated for a specific service. Spread Spectrum Initially devised for military use, this radio transmission technology "spreads" information over greater bandwidth than necessary to resist jamming and other interference. SSL Encryption A method by which information transmitted across the Internet is scrambled to the point where it's virtually indecipherable by anyone who should intercept the data before it reaches its destination. Most reputable online stores make use of SSL encryption to request credit card information and other sensitive data from their customers. Web pages where SSL encryption is activated are typically identified by a lock or key symbol displayed somewhere in your browser. Refer to your browser's documentation for the specific symbol and location. Standby Time The amount of time you can leave your fully charged cellular portable or transportable phone turned on before the phone will completely discharge the batteries. See Talk Time. Strongest Signal The concept that a wireless 911 call should be routed to the cell site with the strongest link to the phone, regardless of which carrier holds the caller as a customer. A shortcoming is that strength of the call's setup link isn't always equal to that of the link the cell assigns for voice traffic because the latter can be weaker. Subscriber Identity Module (SIM) A card inserted into a GSM/TDMA or GSM-only handset containing subscriber-related data. The card contains 18 digits for GSM markets and 20 digits for TDMA markets. TD-CDMA A 3G proposal combining elements of TDMA and CDMA. Third Generation (3G) A new wireless standard promising increased capacity and high-speed data applications up to two megabits. Third generation wireless employ wideband frequency carriers and a CDMA air interface. Networks must be able to transmit wireless data at 144 kilobits per second at mobile user speeds. Implemented in Europe as UMTS and CDMA2000 in North America , its goals are high-quality multimedia and advanced global roaming (in house, cellular, satellite, etc.). Time Division Multiple Access (TDMA) A method of digital wireless communications transmission allowing a large number of users to access a single radio-frequency channel without interference. Each user is given a unique time slot within each channel. SMS Mobile Originate has now gone live on several TDMA networks around the world including Telecom New Zealand , Midwest Wireless USA, Algar Telecom Brazil and Cellcom Israel . Other TDMA network operators such as AT&T Wireless in the U.S. have launched SMS nationally. Transceiver Equipment to handle the broadcast and reception of radio signals with network or subscriber equipment. Tri-Band A network infrastructure or wireless phone designed to operate in three frequency bands: 800 MHz, 900 MHz and 1800MHz. Tri-Mode Phones that work on three modes GSM, TDMA and analog. Universal Mobile Telecommunications System (UMTS) The goal of UMTS is to enable networks that offer true global roaming and can support a wide range of voice, data and multimedia services. A new-generation technology for rapidly moving data and multimedia over wireless devices. The European implementation of the 3G wireless phone system, UMTS provides service in the 2GHz band and offers global roaming and personalized features; designed as an evolutionary system for GSM network operators, multimedia data rates offered by UMTS are: vehicular - 144 kbit/s; pedestrian 384 kbit/s; in-building 2Mb/s. UWC-136 A third-generation wireless standard proposal based on TDMA technology that was developed by the Universal Wireless Communications Consortium and is one of the 3G candidates submitted to the International Telecommunication Union by the United States . UWC-136 represents an evolutionary path for both the old analog Advanced Mobile Phone System (AMPS) and the second-generation TIA/EIA-136 technologies, which were designed specifically for compatibility with AMPS. UWC-136 radio transmission technology proposes a low-cost incremental, evolutionary deployment path for both AMPS and TIA/EIA operators. The technology is tolerant of the frequency band in which it is deployed: 500 MHz to 2.5 GHz. Wideband CDMA (WCDMA) A 3G mobile services platform, based on modern, layered network-protocol structure, similar to the protocol structure used in GSM networks. WCDMA has been designed for high-speed data services and more particularly, internet-based packet-data offering up to 2Mbps in stationary or office environments, and up to 384Kbps in wide area or mobile environments. The third generation radio standard that will offer voice, data, motion-video and other multimedia capabilities, and increases data transmission rates in GSM systems by using CDMA instead of TDMA. WCDMA has become the Direct Sequence (DS) mode in the ITU's 3G specification, which includes the 1X Multi-Carrier mode (1X MC) and 3X Multi-Carrier mode (3X MC). 1X MC (formerly known as cdma2000) and 3X MC comprise the 3G upgrade path for carriers already using CDMA (cdmaOne). Wireless Application Protocol (WAP) An open standard for communication between handsets and the Internet. WAP is a wireless communications environment for delivering web data to wireless terminals with minimal screen display. An initiative started by Unwired Planet, Motorola, Nokia and Ericsson to develop a standard for wireless content delivery on the next generation of mobile communicators. WAP strips all but graphics for display on small screens, such as mobile phones. A mini-browser is an integral part of WAP enabled phones. WAP enabled phones first appeared in Europe at the end of 1999. Wireless Communications Services (WCS) The variety of services available using frequencies in the 2.3 GHz band for general fixed wireless use. Wireless Instant Messaging (WIM) Bridges the gap between wired and wireless networks. WIM seamlessly allows a desktop user to instantly send a message to a handset. Wireless Transport Layer Security (WTLS) The security layer of the WAP which provides privacy, data integrity and authentication for WAP services. WTLS, designed specifically for the wireless environment, is needed for the client and server to be authenticated in order for wireless transactions to remain secure and also because the connection needs to be encrypted. For example, a user making a transaction with a bank over a wireless device needs to know that the connection is secure and private and not subject to a security breach during transfer. WTLS is needed because mobile networks do not provide complete end-to-end security.     < Prev