Tag: physics

WAP allows wireless mobile devices to access the Internet and its services such as the Web and e-mail.

Wireless Application Protocol (WAP) is a technical standard for accessing information over a mobile wireless network. A WAP browser is a web browser for mobile devices such as mobile phones that uses the protocol. Introduced with much hype in 1999, WAP achieved some popularity in the early 2000s, but by the 2010s it had been largely superseded by more modern standards. Most modern handset internet browsers now fully support HTML, so they do not need to use WAP markup for web page compatibility, and therefore, most are no longer able to render and display pages written in WML, WAP's markup language.

Before the introduction of WAP, mobile service providers had limited opportunities to offer interactive data services, but needed interactivity to support Internet and Web applications such as email, stock prices, news and sports headlines. The Japanese i-mode system offered another major competing wireless data protocol.

Voicemails is a personal security code for GSM (global system for mobile communication) subscribers.

GSM (global system for mobile communication) services are a standard collection of applications and features available to mobile phone subscribers all over the world. The GSM standards are defined by the 3GPP collaboration and implemented in hardware and software by equipment manufacturers and mobile phone operators. 

GSM provides recommendations, not requirements. The GSM specifications define the functions and interface requirements in detail but do not address the hardware.

A voicemail system is a computer-based system that allows users and subscribers to exchange personal voice messages; to select and deliver voice information; and to process transactions relating to individuals, organizations, products and services, using an ordinary telephone. The term is also used more broadly to denote any system of conveying a stored telecommunications voice messages, including using an answering machine.

A simple protocol used for fetching e-mail from a remote mailbox is Post Office Protocol which is defined in RFC 1084.

Post office protocol (POP) is an application layer internet standard protocol used by e-mail clients to retrieve e-mail from a server in an internet protocol(IP) network.

Post office protocol (POP) is a message access protocol that enables the client to fetch an e-mail from the remote mail server.

A request for comments (RFC) is a formal document from the internet engineering task force ( IETF ) that is the result of committee drafting and subsequent review by interested parties.

Mobile computers and personal digital assistants (PDAs) are the examples of wireless network.

Personal digital assistant:-

Personal digital assistant is a term for a small, mobile, handheld device that provides computing and information storage and retrieval capabilities for personal or business use, often for keeping schedules, calendars and address book information handy.

Mobile computers:-

Mobile computing is human computer interaction by which a computer is expected to be transported during normal usage, which allows for transmission of data, voice and video.

Wireless network:-

A wireless network is a computer network that uses wireless data connections between network nodes.

In recent years general packet radio service (GPRS) has been deployed to give IP connectivity to GSM users.

General packet radio services (GPRS) is a packet-based wireless communication service that promises data rates from 56 up to 114 Kbps and continuous connection to the internet for mobile phone and computer users. The higher data rates allow users to take part in video conferences and interact with multimedia Web sites and similar applications using mobile handheld devices as well as notebook computers.

General Packet Radio Service (GPRS) is a packet oriented mobile data standard on the 2G and 3G cellular communication network's global system for mobile communications(GSM).

video conferencing used in real time system.

video conferencing system:-

Videoconferencing (or video conference) means to conduct a conference between two or more participants at different sites by using computer networks to transmit audio and video data. For example, a point-to-point (two-person) video conferencing system works much like a video telephone.

Real-time communication is a means of sharing information and interacting with people in different locations via Internet connections, just as if you were talking to each other face-to-face. Apart from audio-only conference call, video conferencing is also one kind of live teleconferencing communications. The advantages of video conference in real-time communication are obvious, and it has been widely applied to host a virtual video meeting or online training in almost every industry.

A transmission in which receiver receives the data simultaneously as it is relayed is called Real-time transmission.

Real Time Transmission:- When you are sending a fax, the machine will scan the document into the memory before sending it. Sometimes, we may want to send an important document immediately, without waiting for memory transmission.

Global system for mobile communication:-

GSM (Global system for mobile communication) is a standard developed by the European telecommunications standards institute (ETSI) to describe the protocols for second-generation digital cellular networks used by mobile devices such as tablets.

GSM uses a variation of time division multiple access (TDMA) and is the most widely used of the three digital wireless telephony technologies: TDMA, GSM and code-division multiple access (CDMA). 

Piggy backing is a technique for Flow control.

The receiver waits until its network layer passes in the next data packet. The delayed acknowledgement is then attached to this outgoing data frame. This technique of temporarily delaying the acknowledgement so that it can be hooked with next outgoing data frame is known as piggybacking.

Piggybacking is a technique used for efficient utilization of bandwidth. The acknowledgment for previous segment is sent along with the data request/transfer of current segment.

Speed of light, c = 3 x 10$^8$ m s$^{-1}$
Time taken by light to reach the earth from the galaxy is
$\displaystyle t = \frac {10^{25}m}{3\times 10^8m\,s^{-1}}\,=\,3\times 10^{16}s$