Bab 2: wawasan dasarBab 2: wawasan dasar sistem komunikasisistem komunikasi

Oleh: nonot harsonoOleh: nonot harsono

Siskom di sekitar kitaSiskom di sekitar kita Telepon: lokal, interlokal, internationalTelepon: lokal, interlokal, international Radio broadcast (siaran): AM (MW), FM (mono, Radio broadcast (siaran): AM (MW), FM (mono,

stereo)stereo) TV broadcast: via Microwave, or SatelliteTV broadcast: via Microwave, or Satellite Telepon seluler: AMPS, GSM, CDMATelepon seluler: AMPS, GSM, CDMA PagerPager Radio dua arah: CB (citizent band), amatir radio Radio dua arah: CB (citizent band), amatir radio

(ORARI), polisi, PMK, dll.(ORARI), polisi, PMK, dll. Komunikasi Data: via jaringan telepon, via Komunikasi Data: via jaringan telepon, via

INTERNETINTERNET dan lain-laindan lain-lain

Jaringan teleponJaringan telepon

STOlokal

STOlokal

STOlokal

STOkab

STOkab

STOkab

STOprop

STOreg

STOprop

STOreg

STOlokal

STOkab

Level regional

Level propinsi

Level kabup

Level kecamatan

Apabila trafik telepon padat, antar kabupaten bisa saja dihubungkanlangsung menggunakan serat optik atau pun Microwave, atau yg lain

Komunikasi Voice/percakapanKomunikasi Voice/percakapan

Komunikasi Voice/telepon memerlukan:Komunikasi Voice/telepon memerlukan:

1.1. Piranti sumberPiranti sumber

2.2. Sistem switching Sistem switching STO telepon atau PBXSTO telepon atau PBX

3.3. Kanal komunikasi Kanal komunikasi jaringan kabel atau radio jaringan kabel atau radio

4.4. Piranti tujuanPiranti tujuan Saluran/kanal/sambungan harus tetap terjaga Saluran/kanal/sambungan harus tetap terjaga

selama terjadi percakapanselama terjadi percakapan Jadi memerlukan dedicated connectionJadi memerlukan dedicated connection

Radio BroadcastRadio Broadcast

SS-FM

100 MHz

Radio siaran FM menempati band frekuensi88 MHz ~ 108 MHzRadio siaran AM(MW) menempati band fre-kuensi 535 kHz ~ 1605 kHz

Transmisi Microwave Terrestrial Transmisi Microwave Terrestrial utk Telepon, TV, Datautk Telepon, TV, Data

30 ~ 50 km

Gelombang mikroMisalnya: 2 GHz

repeaterrepeater

Siskom Satellite Siskom Satellite utk TV, Telepon, Internetutk TV, Telepon, Internet

StasiunPengirim

StasiunPenerima

Up LinkC band = 6 GHz

Down LinkC band = 4 GHz

Cellular TelephoneCellular Telephone

Mobile Switching

Center (MSC)

BTS

Cell 1

Cell 2

Cell 3STO

Telepon rumah

Ke/dari STO lain

ke/dariMSC lain

BTS: base transceiver station

sebutan lain RBS: radio base station

Sistem PagerSistem Pager

PT Pager

148,7 MHz

Kode akses: xxxx

Misal: 4859Kode + sinyal pembawa info

Hanya penerima yang kodenya cocok saja yangakan aktif dan membaca informasi yang dikirim

Radio Dua-arah (two-way)Radio Dua-arah (two-way)pemancar

penerimapemancar

penerima

pemancar

penerimapemancar

penerima

Contoh:1. CB (citizent band) yang bekerja pada frekuensi sekitar

27 MHz atau 11m band; di bawah organisasi RAPI2. Radio Amatir dengan organisasi ORARI-nya; bekerja

dibanyak frekuensi (HF, VHF, UHF), misalnya 80m, 2m band, 470MHz, dll

Transmission TypesTransmission TypesSimplexSimplex transmission, messages can be carried transmission, messages can be carried

in in only one directiononly one direction..Half-duplexHalf-duplex, , messages can be carried in messages can be carried in both both

directionsdirections just just notnot simultaneously. simultaneously.Full-duplexFull-duplex, , messages can be carried in both messages can be carried in both

directions directions simultaneouslysimultaneously..

Komunikasi data adalah komunikasi antar Komunikasi data adalah komunikasi antar komputer baik dalam lingkup yang kecil komputer baik dalam lingkup yang kecil maupun besar (LAN, WAN, MAN, Internet)maupun besar (LAN, WAN, MAN, Internet)

Pengguna Internet meningkat pesat seiring Pengguna Internet meningkat pesat seiring dengan makin banyaknya jenis layanandengan makin banyaknya jenis layanan

Tidak harus menguasai/menduduki saluran Tidak harus menguasai/menduduki saluran end-to-end selama transmisi dataend-to-end selama transmisi data

Menggunakan teknologi “Menggunakan teknologi “packet switchingpacket switching”, ”, artinya data dari sumber tidak dikirim sekaligus artinya data dari sumber tidak dikirim sekaligus tetapi dipecah-pecah menjadi paket-paket keciltetapi dipecah-pecah menjadi paket-paket kecil

Komunikasi Data/komputerKomunikasi Data/komputer

Komunikasi data via jaringan teleponKomunikasi data via jaringan telepon

Computers Computers can onlycan only process digital signals process digital signals If data is transmitted using analog signaling, it If data is transmitted using analog signaling, it

must be converted into a digital signal before the must be converted into a digital signal before the computer can process it……computer can process it……

Ruas jaringan telepon dari rumah ke STO, Ruas jaringan telepon dari rumah ke STO, umumnya adalah untuk voice analogumumnya adalah untuk voice analog

Ruas STO ke STO adalah ruas transmisi digitalRuas STO ke STO adalah ruas transmisi digital Output komputer yang digital harus diubah Output komputer yang digital harus diubah

menjadi nada-nada (analog) agar bisa melewati menjadi nada-nada (analog) agar bisa melewati jaringan teleponjaringan telepon

ModemsModems

MOdulationMOdulation - converting digital signals into - converting digital signals into analog form analog form (=berfungsi mengubah sinyal (=berfungsi mengubah sinyal digital menjadi sinyal analog)digital menjadi sinyal analog)

DEModulationDEModulation - converting analog signals - converting analog signals back into digital form back into digital form (= berfungsi mengubah (= berfungsi mengubah sinyal analog menjadi sinyal digital kembali)sinyal analog menjadi sinyal digital kembali)

BandwidthBandwidth is used to describe the capacity of is used to describe the capacity of a communications mediuma communications medium

BPS, bits per secondBPS, bits per second kHz, kilohertz kHz, kilohertz MHz, megahertzMHz, megahertz

NarrowbandNarrowband (transmission speeds of 64 kbps or (transmission speeds of 64 kbps or less)less)

WidebandWideband (transmission speeds between 64 kbps (transmission speeds between 64 kbps and 1.544 Mbps)and 1.544 Mbps)

BroadbandBroadband (transmission rates of 1.544 Mbps or (transmission rates of 1.544 Mbps or higher)higher)

Data ChannelsData Channels

Ilustrasi ttg Bandwidth (Ilustrasi ttg Bandwidth (domain frekdomain frek))Dikatakan bahwa sinyaloutput dari generator menempati band frekuensiselebar BW Hz, misalnya300 ~ 3400 Hz

Generatorsinyal

frekBW

Output 1.

2.

frekBWin kanal

Sinyal input

frekBWout

Sinyal output

Misalnya BWin = 10 kHz dan BWout = 8 kHz, maka dikatakan bahwa Bandwidth dari kanal adalah sebesar 8 kHz.

3. Perhatikan 2 informasi berikut! 1. Frek = 100 kHz2. BW = 100 kHz

Sudah terbayangkah makna/gambaranfisik dari kedua info tersebut?

frek100kHzfrek100kHz

Ilustrasi ttg Bandwidth (Ilustrasi ttg Bandwidth (domain waktu domain waktu / / digitaldigital))

Sumber data30x64 kbps

64 kbps64 kbps

64 kbps

MUX(multiplexer) 2 Mbps

Sumber data24x64 kbps 1,544 Mbps

Sumberdata

Output: Data dengan “kecepatan”64 kbps (kilo bit per second)

Dikatakan bahwa dataini memiliki bandwidthsebesar 64 kbps

Kanal bisa dilalui data dengan kecepatan maksimum 64 kbps

Maka dikatakan bahwa kanal inimempunyai bandwidth 64 kbps

Sumber data128 kbps

BW = 64 kbps

kata lain: kecepatan akses (access rate)

Sisi penerima

1.

2.

3.

Telecommunication TechnologyTelecommunication Technology ISDNISDN

Integrated service digital networkIntegrated service digital network Allows voice and data on same digital line using Allows voice and data on same digital line using

copper wirecopper wire up to 1.5 Mbpsup to 1.5 Mbps

DSLDSL digital subscriber line technologydigital subscriber line technology up to 8 Mbps over copper wire.up to 8 Mbps over copper wire.

Cable ModemsCable Modems allow transmission of Internet traffic through the allow transmission of Internet traffic through the

cable TV network. cable TV network. Up to 2.5 Mbps (not all are two-way)Up to 2.5 Mbps (not all are two-way)

Teknologi transmisi digitalTeknologi transmisi digital T-carrier systems are digital transmission T-carrier systems are digital transmission

systems that take analog voice circuits and systems that take analog voice circuits and converts them to digital form for transmission. converts them to digital form for transmission. Companies typically lease T lines.Companies typically lease T lines.

T1 – 1.5 MbpsT1 – 1.5 Mbps T2 – 6.3 MbpsT2 – 6.3 Mbps T3 – 44.7 MbpsT3 – 44.7 Mbps T4 – 274.2 MbpsT4 – 274.2 Mbps

E1 – 2 MbpsE2 – 8 MbpsE3 – 32 MbpsE4 – 128 MbpsE5 – 512 Mbps

Communication ProtocolCommunication Protocol A A communication protocolcommunication protocol is essentially a set of is essentially a set of

codes or conventions used for facilitating codes or conventions used for facilitating communications between hardware and software.communications between hardware and software. IPIP or Internet Protocol directs packets on the or Internet Protocol directs packets on the

Internet.Internet. TCPTCP or Transmission control protocol puts the or Transmission control protocol puts the

packets in their correct sequence.packets in their correct sequence. HTTPHTTP or hyper text transfer protocol is used to or hyper text transfer protocol is used to

transmit web pages over the Internet.transmit web pages over the Internet. Mobile IPMobile IP provides IP routing for mobile devices. provides IP routing for mobile devices.

ProtocolProtocol Sekumpulan aturan main yang memungkinkan Sekumpulan aturan main yang memungkinkan

komponen-komponen jaringan untuk bisa saling komponen-komponen jaringan untuk bisa saling berkomunikasi satu dengan yang lainberkomunikasi satu dengan yang lain handshaking protocolhandshaking protocol

identify each deviceidentify each devicesecure attention of other devicesecure attention of other device

transmission protocoltransmission protocol verify correct receipt of messageverify correct receipt of messagesend re-transmit message if necessarysend re-transmit message if necessaryrecover error and re-transmitrecover error and re-transmit

Computer NetworksComputer Networks

A A computer networkcomputer network is used to connect is used to connect multiple uses and computing devices multiple uses and computing devices together, together, using telecommunications using telecommunications technologiestechnologies..

Computer NetworksComputer Networks

Two types of networksTwo types of networks Server-based networksServer-based networks Peer-to-peer networksPeer-to-peer networks

Four classes of networksFour classes of networks Local Area Network (Local Area Network (LANLAN)) Metropolitan Area Network (Metropolitan Area Network (MANMAN)) Wide Area Network (Wide Area Network (WANWAN)) Personal Area Network (Personal Area Network (PANPAN))

Peer to peer vs server basedPeer to peer vs server based

Computer NetworksComputer Networks

How are they physically set up?How are they physically set up?STARSTARBUSBUSToken RingToken Ring

Network TopologyNetwork Topology

StarStarcentral host is connected to several other central host is connected to several other

computerscomputersall communications must pass through the all communications must pass through the

hosthost

Network TopologyNetwork Topology

BusBuscomputers are linked by a single loop circuitcomputers are linked by a single loop circuitall messages transmitted over entire networkall messages transmitted over entire networkdata pass in either directiondata pass in either direction

Network TopologyNetwork Topology

Token RingToken Ring number of computers are linked by a closed number of computers are linked by a closed

looploop data passes in a single directiondata passes in a single direction

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