Wednesday, November 29, 2006

Mobile phone

A mobile or cellular telephone is a long-range, portable electronic device for personal telecommunications over long distances. It is of great use to many people.

Most current mobile phones connect to a cellular network of base stations (cell sites), which is in turn interconnected to the public switched telephone network (PSTN) (the exception are satellite phones). Fully automatic cellular networks were first introduced in the early to mid 1980s (the 1G generation). The first fully automatic cell phone system was the Nordic Mobile Telephone (NMT) system, introduced in 1981.

Prior mobile telephones (the so-called 0G generation), such as Mobile Telephone Service, date back to 1945. These were not categorized as cellular phones, since they did not support handover, i.e. automatic change of channel frequency in the middle of a call, when the user moved from one cell (base station coverage area) to another.

Until the mid to late 1980s, most mobile phones were sufficiently large that they were permanently installed in vehicles as car phones. With the advance of miniaturization, currently the vast majority of mobile phones are handheld. In addition to the standard voice function of a telephone, a mobile phone can support many additional services such as SMS for text messaging, email, packet switching for access to the Internet, and MMS for sending and receiving photos and video.

The world's largest mobile phone manufacturers include Audiovox, BenQ-Siemens, High Tech Computer Corporation, Fujitsu, Kyocera, LG, Motorola, NEC, i-mate, Nokia, Panasonic (Matsushita Electric), Pantech Curitel, Philips, Sagem, Samsung, Sanyo, Sharp, Siemens SK Teletech, Sony Ericsson, T&A Alcatel, T-Mobile, and Toshiba.

The world's largest mobile phone operators (based on customer totals) include China Mobile, Vodafone, and China Unicom.

There are also specialist communication systems related to, but distinct from mobile phones, such as Professional Mobile Radio. Mobile phones are also distinct from cordless telephones, which generally operate only within a limited range of a specific base station. Technically, the term mobile phone includes such devices as satellite phones and pre-cellular mobile phones such as those operating via MTS which do not have a cellular network, whereas the related term cell(ular) phone does not. In practice, the two terms are used nearly interchangeably, with the preferred term varying by location. There are lots of different networks on mobile phones. Some are pay as you go, where you can buy top ups and add them to your phone, so there is no monthly bill, and some are pay monthly. This means you get a bill every month for how much calls and texts you make.

Martin Cooper is widely considered to be the inventor of the cell phone. Using a modern, if somewhat heavy portable handset, Cooper made the first call on a cell phone in 1973. At the time he made his call, Cooper was working as Motorola's General Manager of its Communications Division. Motorola had developed the idea of using cellular communications on a portable platform (i.e., a handset)in a non-vehicle setting.

Mock-up of the "portable phone of the future," from a mid-60s Bell System advertisement, shows a device not too different from today's mobile telephones.Radiophones have a long and varied history that stretches back to the 1950s, with hand-held cellular radio devices being available since 1983. Due to their low establishment costs and rapid deployment, mobile phone networks have since spread rapidly throughout the world, outstripping the growth of fixed telephony.

Luxembourg has the highest mobile phone penetration rate in the world, at 164% in December 2005. The total number of mobile phone subscribers in the world was estimated at 2.14 billion in 2005.. Around 80% of world's population have mobile phone coverage as of 2006. This figure is expected to increase to 90% by the year 2010.

At present, Africa has the largest growth rate of cellular subscribers in the world. African markets are expanding nearly twice as fast as Asian markets. The availability of Prepaid or pay as you go services, where the subscriber does not have to commit to a long term contract, has helped fuel this growth on a monumental scale, not only in Africa but on other continents as well.

All European nations and most Asian and African nations have adopted GSM. In other countries, such as the United States, Australia, Japan, and South Korea, legislation does not require any particular standard, and GSM coexists with other standards, such as CDMA and iDEN.

Saturday, August 26, 2006

Albert Einstein

Albert Einstein was born at Ulm, in Württemberg, Germany, on March 14, 1879. Six weeks later the family moved to Munich and he began his schooling there at the Luitpold Gymnasium. Later, they moved to Italy and Albert continued his education at Aarau, Switzerland and in 1896 he entered the Swiss Federal Polytechnic School in Zurich to be trained as a teacher in physics and mathematics. In 1901, the year he gained his diploma, he acquired Swiss citizenship and, as he was unable to find a teaching post, he accepted a position as technical assistant in the Swiss Patent Office. In 1905 he obtained his doctor's degree.During his stay at the Patent Office, and in his spare time, he produced much of his remarkable work and in 1908 he was appointed Privatdozent in Berne. In 1909 he became Professor Extraordinary at Zurich, in 1911 Professor of Theoretical Physics at Prague, returning to Zurich in the following year to fill a similar post. In 1914 he was appointed Director of the Kaiser Wilhelm Physical Institute and Professor in the University of Berlin. He became a German citizen in 1914 and remained in Berlin until 1933 when he renounced his citizenship for political reasons and emigrated to America to take the position of Professor of Theoretical Physics at Princeton*. He became a United States citizen in 1940 and retired from his post in 1945.After World War II, Einstein was a leading figure in the World Government Movement, he was offered the Presidency of the State of Israel, which he declined, and he collaborated with Dr. Chaim Weizmann in establishing the Hebrew University of Jerusalem.Einstein always appeared to have a clear view of the problems of physics and the determination to solve them. He had a strategy of his own and was able to visualize the main stages on the way to his goal. He regarded his major achievements as mere stepping-stones for the next advance.At the start of his scientific work, Einstein realized the inadequacies of Newtonian mechanics and his special theory of relativity stemmed from an attempt to reconcile the laws of mechanics with the laws of the electromagnetic field. He dealt with classical problems of statistical mechanics and problems in which they were merged with quantum theory: this led to an explanation of the Brownian movement of molecules. He investigated the thermal properties of light with a low radiation density and his observations laid the foundation of the photon theory of light.In his early days in Berlin, Einstein postulated that the correct interpretation of the special theory of relativity must also furnish a theory of gravitation and in 1916 he published his paper on the general theory of relativity. During this time he also contributed to the problems of the theory of radiation and statistical mechanics.In the 1920's, Einstein embarked on the construction of unified field theories, although he continued to work on the probabilistic interpretation of quantum theory, and he persevered with this work in America. He contributed to statistical mechanics by his development of the quantum theory of a monatomic gas and he has also accomplished valuable work in connection with atomic transition probabilities and relativistic cosmology.After his retirement he continued to work towards the unification of the basic concepts of physics, taking the opposite approach, geometrisation, to the majority of physicists.Einstein's researches are, of course, well chronicled and his more important works include Special Theory of Relativity (1905), Relativity (English translations, 1920 and 1950), General Theory of Relativity (1916), Investigations on Theory of Brownian Movement (1926), and The Evolution of Physics (1938). Among his non-scientific works, About Zionism (1930), Why War? (1933), My Philosophy (1934), and Out of My Later Years (1950) are perhaps the most important.Albert Einstein received honorary doctorate degrees in science, medicine and philosophy from many European and American universities. During the 1920's he lectured in Europe, America and the Far East and he was awarded Fellowships or Memberships of all the leading scientific academies throughout the world. He gained numerous awards in recognition of his work, including the Copley Medal of the Royal Society of London in 1925, and the Franklin Medal of the Franklin Institute in 1935.Einstein's gifts inevitably resulted in his dwelling much in intellectual solitude and, for relaxation, music played an important part in his life. He married Mileva Maric in 1903 and they had a daughter and two sons; their marriage was dissolved in 1919 and in the same year he married his cousin, Elsa Löwenthal, who died in 1936. He died on April 18, 1955 at Princeton, New Jersey.

Thursday, June 16, 2005


Phone cards

The Continental phone card is one of the most versatile cards on the market. Along with the highest quality service and low rates for many destinations, it also has many handy features (see list below). It is a refillable card with PIN-less dialing, Speed Dial and Online Call History access. The Continental card stands for functionality and convenience.

· No Connection Fee
· Maintenance Fee - No
· Rounding - 3 minutes
· Toll Free Access Numbers - Yes
· Local Access Numbers - Yes
· Service Taxes & Surcharges - 15%
· Pay Phone Charge - 79c
· Validity period - 6 months from last refill/purchase
· Prompt Languages - English

Continental » PC-to-Phone

Continental » PC-to-Phone

How It Works

Use your Internet connection and your computer or any other SIP equipment to call any landline or cell phone.
Install a Softphone, enter your account login and password and start calling! Yes, it's that simple!

Sound card
Headphones or external speakers
Internet connection 64 Kbps +

Continental » WEB-Call

Continental WEB-Call

Connect two phones anywhere in the world

How it works
Enter your phone number
Enter your destination number
Click Call.

Your phone will ring in a few seconds.

Yes, it's that easy!

Rates are better than regular calling cards
Same low rates for either directions
No pin needed to place a call
No software to download and install
Easy-to-use phone book
Accessible from anywhere in the world

Card and Rate Details:
No Connection Fee
Maintenance Fee - No
Rounding - 3 Minute
Service Taxes & Surcharges - 15%
Validity period - 6 months from last refill/purchase