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Datacommunicatie

Systeem 1 Systeem 2

datacommunicatie kanaal

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Data communicatie

A B

A B

A B

Simplex

Half-duplex

Full-duplex

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serieel, parallel

Bits per seconde (bps) < - > Bytes per (Bps)seconde

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Baud

The number of signaling elements that occur each second. The term is named after J.M.E. Baudot, the inventor of the Baudot telegraph code.

element

bijvoorbeeld 4 niveaus

00011011

twee bits

In dat geval: bit rate = 2 x baud rate

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Multiplexen

Multiplexer Demultiplexer

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TDM versus FDM

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Parallel (Strobed)

data

ready

ready

data

een strobe is een opgaande of neergaande flank

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Parallel (Handshaked)

data

Req

Ack

Req

Ack

data

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Serieel (bit Synchroon)

Shift register

Data buffer

Serial data

Parallel data

Shift (transmit) clockTc

receiver

PLL

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Clock extraction options

• rely on (very) accurate clocks

• bit stuffing

• Manchester encoding

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Serieel (frame synchroon)(tijdelijk synchroon)

idle

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Serieel (asynchroon)

Shift register

Data buffer

Serial data

Parallel dataStart bit

data bit

data bit

Par bit

Stop bit

trigger samples

(~ byte synchroon)

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Modulatie: AM, FM, PM

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Modem (modulator/demodulator)

DTE DTEDCE DCE

Data Terminal

Equipment

Data Communication

Equipment

V24 of RS 232

V21 … V34

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Nullmodem

DTE DTE

Data Terminal

Equipment

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RS-232 signal

Single-ended

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RS-422

Differentiële verbinding

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RS-485

Bussysteem (TRI-state)

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Master slave

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Integrated Services Digital Network (ISDN)

There are two types of ISDN:

Basic Rate Interface (BRI) -- consists of two 64-Kbps B-channels and one D-channel for transmitting control information.

Primary Rate Interface (PRI) -- consists of 23 B-channels and one D-channel (U.S.) or 30 B-channels and one D-channel (Europe).

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ISDN NT1/2

B-kanaal 64 kb

D-kanaal 16 kb2B+1D+48 kb (interne signalering) = 192 kb

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(Asymmetric) Digital Subscriber Link

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Opdracht

bestudeer hoofdstuk 10