01-04-2020-Oxford_English_for_Infomation_Technology (1171844), страница 18
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He believes that mobilephones are going to become morelike palmtop computers.Some phones comewith miniaturekeyboards that slotinto the bottom.HOW DATA IS SENTData, cut intopackets, is sentin sequence tothe receiver,which buildsthem backtogether.One time slotcan be shared atthe same timeby many users.The user isalways on-linebut is onlycharged for theamount of datatransmitted.Internet Wap allows you to deliveronline services to a handheldcomputer. People are also expectedto use Waps to access online newsand financial services, sports scoresand entertainment information,most of which you should be able toreach by scrolling down a set menubar.
You will also be able to booktickets by Wap.Email Sending emails is likely to bethe application that is used mostoften, as people will be able to pickup messages at any time fromanywhere in the world.Games Gambling and games, someof which can be downloaded, arealso expected to be popular withusers. But you can, of course, use theWap to make regular phone calls.110UNIT 16 Communications SystemsLANGUAGE WORKPredictions 1: certainty expressions Rank these predictionsaccording to how certain the speakers are. Put the most certain atthe top of your list and the least certain at the bottom.
Somepredictions can have equal ranking.a Wap phones will revolutionise the way we communicate.b Wap phones may revolutionise the way we communicate.c It's likely Wap phones will revolutionise the way wecommunicate.d It's unlikely Wap phones will revolutionise the way wecommunicate.e It's expected Wap phones will revolutionise the way wecommunicate.f It's probable Wap phones will revolutionise the way wecommunicate.g It's possible Wap phones will revolutionise the way wecommunicate.h Wap phones will certainly revolutionise the way wecommunicate.Study this list of certainty expressions:MOREwill, will notcould, may, mightcertainlycertainlikely, unlikelyexpectedprobablyprobablepossiblypossibleLESSListen to this expert talking about future developments incomputing. Note down his predictions. Then listen again and notethe certainty expressions he uses.The recording was made in 2000. Has the situation changedtoday? Discuss in groups.UNIT 16 Communications Systems111Make statements about these predictions for the next fiveyears.
Use the certainty expressions above. For example:All school children in my country will have mobile phones./ think it's unlikely that all school children will have mobile phonesbut it's probable that many of the older pupils will have them.1ATM machines will use iris recognition rather than PINnumbers. You will get access to your account by looking at themachine.2People will vote in elections online.3Taxis will be robot-controlled.4TV journalists will be able to transmit what they see by usingsensors in their optic nerves.5There will be more robots than people in developed countries.6Most computers will be voice-controlled.7Mobile phones will replace computers as the commonest wayto access the Internet.8English will no longer be the commonest language for websites.9Email will be replaced by a voice-based system.10 Computers will become more powerful.PROBLEM-SOLVINGTry to write these two text message poems in standardEnglish.
Compare your versions with others in your group.txtin iz messm,14: a txt msg pom,mi headn'me englis,his is r bunsn brnr bl%,try2rite essays,his hair lykfe filingsthey all come out txtis.gran not plsed w/lettersw/ac/dc going thru'.shes getn,I sit by him in kemistry,swears i wrote betterit splits my @omsb4comin2uni.wen he :-)s @ me.& she's african.Hetty HughesJulia Bird, Poetry Book Society112UNIT 16 Communications SystemsSPEAKINGThe world of connectivity Work in pairs, A and B. Completeyour diagram classifying computer-mediated communication systemswith the help of your partner.Student AStudent BYour diagram is on page 187.Your diagram is on page 193.Together work out where to add these forms of communicationto your diagram.pagersMOOsWRITINGThe Global Positioning System Link each set of sentences tomake one sentence.
You may omit, change or add words as required.Then form your sentences into two paragraphs to make a descriptionof how the GPS works and its uses.1The GPS was developed by the US military.It was designed to pinpoint locations.The locations could be anywhere in the world.2It consists of 24 earth-orbiting satellites.The satellites are 17, 000 kms. above the earth.3Each satellite broadcasts a coded radio signal.The signal indicates the time and the satellite's exact position.4The satellites have atomic clocks.The clocks are accurate to one second every 70, 000 years.5 A GPS receiver contains a microprocessor.The microprocessor compares signals.The signals are from at least three satellites.The microprocessor calculates the latitude, longitude andaltitude of the receiver.UNIT 16 Communications Systems6GPS has many uses apart from military uses.GPS can be used for orienting hikers.GPS can be used for aiding the navigation of ships.GPS can be used for tracking trucks and buses.GPS can be used for locating stolen cars.113114UNIT 16 Communications SystemsBFind the answers to these questions in thefollowing text.1How many channels does an ISDN systemcommonly use?What types of wireless systems are namedin the text?What do PCs connected to a satellite systemuse to send data?What types of cables are used in cablenetwork systems?What may need to be upgraded when usinga shielded DSL system?Compared to the downstream bandwidth,the upstream bandwidth in an ADSL line is:a largerb smallerc the sameWhich type of broadband service is thecheapest?234567BroadbandCommunicationsIntegrated Services DigitalNetwork (ISDN)ISDN services can be carried overexisting telephone network infrastructureto terminal adapters (TAs) in the clientmachine.
A common ISDN interfacestandard has a digital communicationsline consisting of three independentchannels: two Bearer (B) channels, eachat 64Kbit/s, and one Data (D) channel at16Kbit/s. The D channel is used to carrysignalling and supervisory information tothe network, while the B channels carrythe data and can be linked to provide a128Kbit/s data channel.Wireless connectionsThe wireless alternatives come in twoforms: satellite and cellular. Satellitesystems require the use of a modem tomaintain the upload.
Downstreambandwidth is provided via a dedicatedsatellite dish, connector hardware andproprietary software.Cellular systems use assigned radiofrequencies and are based around anetwork of transmitters that are arrangedin a cellular network, much like cellularmobile phone systems.The cable alternativeCable companies can also offer affordablebroadband services over copper coaxialor fibre infrastructure networks. TheUNIT 16 Communications Systemsconnection is shared by several customerson a branch, so actual connection ratesare variable, unlike ISDN and DSL.Digital Subscriber Line (DSL)DSL technology capitalises on theexisting network of copper infrastructure,but allows digital signals to be carriedrather than analogue.
It allows the fullbandwidth of the copper twisted-pairtelephone cabling to be utilised.BDSL-based services are a very low-costoption when compared to other solutionsoffering similar bandwidth, so they canbe made available to the customer atextremely competitive prices.[Adapted from 'Infrastructure for Streaming Video', PC Magazine,lulv 19991Re-read the text to find the answers tothese questions.1 Match the terms in Table A with thestatements in Table B.Table Aa ISDNb TAcData channeld Bearer channelWith splitter-based services, the DSLsignal is pulled out from the phone line asit enters your premises and is wiredseparately to a DSL modem. Thisinvolves additional hardware andinstallation by the service provider at thecustomer site.
The shielded optioninvolves no installation, but the telephonecompany's equipment and some of yourequipment might need upgrading.With Asymmetric Digital Subscriber Line(ADSL), most of the duplex bandwidth isdevoted to the downstream direction,with only a small proportion ofbandwidth being available for upstream.Much Internet traffic through the client'sconnection, such as Web browsing,downloads and video streaming, needshigh downstream bandwidth, but userrequests and responses are less significantand therefore require less on theupstream. In addition, a small proportionof the downstream bandwidth can bedevoted to voice rather than data,allowing you to hold phone conversationswithout requiring a separate line.115eDSLfSplitter-based servicesgADSLTable BiDSL system that separates the digitalsignals from the analogue signalsiiDigital channel used to carry ISDNsignalling and supervisory information tothe networkiii Device installed on a PC to allow it toreceive ISDN signalsiv Integrated Services Digital Networkv Asymmetric Digital Subscriber LineviDigital channel used to carry ISDN datavii Digital Subscriber Line2 Mark the following statements as True orFalse:abcdefgISDN can only operate over a special digitaltelephone line.Two ISDN channels can be combined to givethe user double the bandwidth.Computers connected to a satellite systemdo not need a modem.Cellular networks work in a similar way tomobile phone systems.DSL systems require a special digitaltelephone line.DSL systems use analogue signals.You need a separate line to hold normalphone conversations on an ADSL system.UNIT 17Computing SupportSTARTERFind out what the most common computing problems are foryour classmates and how they get help with these problems.
Usethis form to record your results.ProblemsSources of helpvirusesmonitor problemsmouse problemscomputer hangsprinter problemscomputer crashesotherAsk questions like these:12345LISTENINGHave you ever had a problem with a virus?Have you ever had a software problem?What kind of problem?What did you do about it?How did you get help?Study this form used by computing support staff in a helpcentre to record problems reported by phone. What questions wouldyou ask to get this information? Compare your questions with yourpartner.Now listen to this recording of a computing supportofficer, David, advising a user. Complete the form to record the maindetails of the problem.Listen again to note the questions asked by David. Howdo they compare with the questions you produced in Task 2?Fig 1118UNIT 17 Computing SupportLANGUAGE WORKDiagnosing a fault arStudy this extract from the recording:It sounds as if you may have a driver fault.David is trying to identify the cause of theproblem.
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