1.0 Introduction A computer network is a system of interconnected computers and peripheral devices. For example, it may connect computers, printers, scanners and cameras. Using hardware and software, these interconnected computing devices can communicate with each other through defined rules of data communications. In a network, computers can exchange and share information and resources. A computer network may operate on wired connections or wireless connections. When two or more networks are linked or connected and are able to communicate with one another using suitable hardware and software, it is called an internet work. Meanwhile, communications is about the transfer of information from a sender, across a distance, to a receiver. Using electricity, radio waves or light, information and data in the form of codes are transmitted through a physical medium such as wire, cable, or even the atmosphere.Therefore, in order to make communications possible from computers, across telephones and radios and back to computers and other digital devices again, there must be a signal translator, which we call a modem. The modem, which is short – for modulator or demodulator, converts digital signals into analog and back again into digital signals for information to move across the telephone line. 1
1.0 IntroductionA computer network is a system of interconnected
computers and peripheraldevices. For example, it may connect
computers, printers, scanners andcameras. Using hardware and
software, these interconnected computing devices cancommunicate
with each other through defined rules of data communications.In
anetwork, computers can exchange and share information and
resources. A computernetwork may operateon wiredconnectionsor
wirelessconnections. Whentwo ormorenetworks arelinkedor
connectedandareabletocommunicatewithoneanother using suitable
hardware and software, it is called an internet work.eanwhile,
communications is about thetransfer of
informationfromasender,across a distance, to a receiver. Using
electricity, radio waves or light, informationand data in the form
of codes are transmitted through a physical medium such aswire,
cable, oreventheatmosphere.!herefore,
inordertomakecommunicationspossible from computers, across
telephones and radios and back to computers andother digital
devicesagain, theremust beasignal translator, whichwecall "amodem.
!he modem, which is short for modulator or demodulator, converts
digitalsignals into analog and back again into digital signals for
information to move acrossthe telephone line.#2.0 Mobile
Computing2.1 Definitionobile computing is human computer
interaction by whicha computer is expected to be transported during
normal usage. obile computinginvolves mobile communication, mobile
hardware, and mobile software.$ommunicationissues include adhoc
andinfrastructure networks as well ascommunication properties,
protocols, data formats and concrete technologies.%ardwareincludes
mobiledevices or devicecomponents. obilesoftware dealswith the
characteristics and re&uirements of mobile applications.2.2
Specification and frequences of Mobile Computing2.2.1
Specification'( 'lobal (ystem for obile$)A $ode )ivision ultiple
Access%(*A %igh (peed *acket Access+,)- +volution.)ata -ptimi/ed0!+
0ong.!erm +volution12.2.2 Servicesessaging.iessage.((.(.+mail.*ush
+mailWeb 2rowser .%!03 4(afari56ava.i$loud
$loud.!,.-ut.aps.-rgani/er.,oice memo.i!unes2.2.3 Frequencies.'(
7389:889#7889#:88.%()*A 7389:889#;889#:8891#883.0 Internet
ec!nolog" and Services3.1 #oI$,oice.over.Internet *rotocol 4,oI*5
is a methodology and group oftechnologies for the delivery of voice
communications and multimedia sessions
