|
Cellular Digital Packet Data
Cellular Digital Packet Data (CDPD) is an obsolete wide-area mobile data service which used unused bandwidth normally used by Advanced Mobile Phone System (AMPS) mobile phones between 800 and 900 MHz to transfer data. Speeds up to 19.2 kbit/s were possible, though real world speeds seldom reached higher than 9.6 kbit/s. The service was discontinued in conjunction with the retirement of the parent AMPS service; it has been functionally replaced by faster services such as 1xRTT, Evolution-Data Optimized, and UMTS/High Speed Packet Access (HSPA). Developed in the early 1990s, CDPD was large on the horizon as a future technology. However, it had difficulty competing against existing slower but less expensive Mobitex and DataTAC systems, and never quite gained widespread acceptance before newer, faster standards such as General Packet Radio Service (GPRS) became dominant. CDPD had very limited consumer products. AT&T Wireless first sold the technology in the United State ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bandwidth (signal Processing)
Bandwidth is the difference between the upper and lower Frequency, frequencies in a continuous Frequency band, band of frequencies. It is typically measured in unit of measurement, unit of hertz (symbol Hz). It may refer more specifically to two subcategories: ''Passband bandwidth'' is the difference between the upper and lower cutoff frequencies of, for example, a band-pass filter, a communication channel, or a signal spectrum. ''Baseband bandwidth'' is equal to the upper cutoff frequency of a low-pass filter or baseband signal, which includes a zero frequency. Bandwidth in hertz is a central concept in many fields, including electronics, information theory, digital communications, radio communications, signal processing, and spectroscopy and is one of the determinants of the capacity of a given communication channel. A key characteristic of bandwidth is that any band of a given width can carry the same amount of information, regardless of where that band is located in the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AT&T Wireless
AT&T Mobility, LLC, also known as AT&T Wireless and marketed as simply AT&T, is an American telecommunications company. Formed in April 2000 as Cingular Wireless LLC, It is a wholly owned subsidiary of AT&T Inc. and provides wireless services in the United States. AT&T Mobility is the third largest wireless carrier in the United States, with 118 million subscribers as of March 31, 2025. The company is headquartered in Brookhaven, Georgia. Originally known as Cingular Wireless (a joint venture between SBC Communications and BellSouth) from 2000 to 2007, the company acquired the old AT&T Wireless in 2004; SBC later acquired the original AT&T and adopted its name. Cingular became wholly owned by AT&T in December 2006 as a result of AT&T's acquisition of BellSouth. In January 2007, Cingular confirmed it would rebrand itself under the AT&T name. Although the legal corporate name change occurred immediately, for both regulatory and brand-awareness reasons both brands were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 contiguous states border Canada to the north and Mexico to the south, with the semi-exclave of Alaska in the northwest and the archipelago of Hawaii in the Pacific Ocean. The United States asserts sovereignty over five Territories of the United States, major island territories and United States Minor Outlying Islands, various uninhabited islands in Oceania and the Caribbean. It is a megadiverse country, with the world's List of countries and dependencies by area, third-largest land area and List of countries and dependencies by population, third-largest population, exceeding 340 million. Its three Metropolitan statistical areas by population, largest metropolitan areas are New York metropolitan area, New York, Greater Los Angeles, Los Angel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telemetry
Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek roots ''tele'', 'far off', and ''metron'', 'measure'. Systems that need external instructions and data to operate require the counterpart of telemetry: telecommand. Although the term commonly refers to wireless data transfer mechanisms (e.g., using radio, ultrasonic, or infrared systems), it also encompasses data transferred over other media such as a telephone or computer network, optical link or other wired communications like power line carriers. Many modern telemetry systems take advantage of the low cost and ubiquity of GSM networks by using SMS to receive and transmit telemetry data. A ''telemeter'' is a physical device used in telemetry. It consists of a sensor, a transmission path, and a display, recording, or control device. Electronic devices are widely u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EarthLink Wireless
EarthLink is an American Internet service provider. Earthlink went public on NASDAQ in January 1997. Much of the company's growth was via acquisition. In 2000, ''The New York Times'' described it as the "second largest Internet service provider after America Online". Overview EarthLink was formed in 1994, and offers services to residential consumers and businesses. EarthLink claims to have five million users. EarthLink business Internet sells business telecom services, IT and virtualization, cloud computing, IT security, digital marketing, colocation, hosted applications, and support services. In 2014, the company stated it owned and operated a U.S. network including 29,421 route miles of fiber, 90 metro fiber rings, and eight data centers. EarthLink's residential consumer services include wireless, fiber, and satellite internet, streaming content bundles, web hosting and e-commerce. Its products include spam filters, anti-virus protection, and cloud storage. Private equity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palm V
Palm V is a personal digital assistant (PDA) by 3Com. Released in 1999 by 3Com, the PDA has an aluminum enclosure containing a Dragonball EZ central processing unit (capable of overclocking to 39 MHz) and two megabytes of memory. Measuring tall and less than thick, the device's 16-shade grayscale display has a backlight and increased resolution from the previous-generation Palm III. Unlike that older device, which uses disposable batteries ( AAAs), the Palm V has a built-in rechargeable lithium-ion battery with an expected charge lasting 1–2 weeks. Palm Vs are equipped with a serial port that is electrically though not physically compatible with the EIA-232-D telecommunications standard (the redesigned enclosure design prevents Palm III-compatible accessories from connecting to the port) and a Consumer IR transceiver. Upon launch, the Palm V cost about , though it had reduced to –400 by January 2000 (equivalent to about $– in ). Units sold in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OmniSky
OmniSky was a dotcom-era Silicon Valley startup, focused on web-enabled, wireless, mobile touchscreen products and services. Their wireless connectivity was built on CDPD technology. The modems supported Palm V and Handspring, Inc. Visor handhelds. OmniSky produced the first touchscreen handset to integrate Google's search engine. OmniSky was founded on May 7, 1999 and held an IPO through NASDAQ The Nasdaq Stock Market (; National Association of Securities Dealers Automated Quotations) is an American stock exchange based in New York City. It is the most active stock trading venue in the U.S. by volume, and ranked second on the list ... on September 21, 2000. It generated no revenue in 1999 and prior to its IPO it reported a lifetime total of $2.1 million revenue compared to a loss of more than $40 million. By November 2001 OmniSky reported that it was no longer able to complete its financial statements due to a possible pending bankruptcy. OmniSky sold to EarthLink in D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apple Newton
The Newton is a specified standard and series of personal digital assistants (PDAs) developed and marketed by Apple Inc., Apple Computer, Inc. from 1993 to 1998. An early device in the PDA categorythe term itself originating with the Newtonit was the first to feature handwriting recognition. Newton devices run on a proprietary operating system, Newton OS; unlike the company's Mac (computer), Macintosh computers, Apple licensed the software to third-parties, who released Newton devices alongside Apple's own MessagePad line. Apple started developing the platform in 1987; concepted by Steve Sakoman as a Tablet computer, tablet-like device with handwriting capabilities, he worked with AT&T Corporation to develop a low-power processor, AT&T Hobbit, Hobbit, for the project. However, slow progress and other issues led to Sakoman leaving Apple in 1990 to form Be Inc., Be Computer, Inc. The Newton project would be revitalized by Michael Tchao and Steve Capps who pitched the idea directly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Ocean
Digital Ocean, Inc. was a maker of wireless products from 1992 until it was disbanded in 1998. History The company was founded in May 1992 by Jeffery Alholm and headquartered in Lenexa, Kansas. The company had several contracts with Apple Inc., AT&T, Aironet Wireless Communications (later acquired by Cisco as its wireless LAN division), Harris Semiconductor, the United States Department of Defense. It was a co-developer of the IEEE 802.11 wireless standard and of the industry's first 802.11 chipset. It developed the Seahorse, arguably the world's first smartphone. In addition, by specializing in rapid, custom development, the company concluded multiple individual development contracts for application-specific wireless products in vertical markets. Digital Ocean was granted approximately 20 patents for its development of wireless technologies. In 1998 it was sold with its assets to Harris Semiconductor to become part of their Intersil division; Intersil was then spun off f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GPRS
General Packet Radio Service (GPRS), also called 2.5G, is a mobile data standard on the 2G cellular communication network's Global System for Mobile Communications, global system for mobile communications (GSM). Networks and mobile devices with GPRS started to roll out around the year 2001; it offered, for the first time on GSM networks, seamless data transmission using Packet switching, packet data for an "always-on" connection (eliminating the need to "dial-up"), so providing improved Internet access for World Wide Web, web, email, Wireless Application Protocol, WAP services, Multimedia Messaging Service (MMS) and others. Up until the rollout of GPRS, only circuit switched data was used in cellular networks, meaning that one or more radio channels were occupied for the entire duration of a data connection. On the other hand, on GPRS networks, data is broken into small packets and transmitted through available channels. This increased efficiency also gives it theoretical data ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Advanced Mobile Phone System
Advanced Mobile Phone System (AMPS) was an analog mobile phone system standard originally developed by Bell Labs and later modified in a cooperative effort between Bell Labs and Motorola. It was officially introduced in the Americas on October 13, 1983,Private Line and was deployed in many other countries too, including Israel in 1986, Australia in 1987, Singapore in 1988, and Pakistan in 1990. It was the primary analog mobile phone system in North America (and other locales) through the 1980s and into the 2000s. As of February 18, 2008, carriers in the United States were no longer required to support AMPS and companies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
