1CSNW1 – week 3 Datacommunicatie

1CSNW1 – week 3Datacommunicatie

Datacommunicatie?

Communications men string telephone wire on an Enewetok tree.

National Park Service(USA)

Datacommunicatie ?

PU-1 MEMORY I/O

Adresbus

databus

besturingsbus

PU-2

Tightly coupled

Multi processor

Datacommunicatie (1)

Systeem 1 Systeem 2

loosely coupled, via (extern) netwerk

datacommunicatie kanaal

Datacommunicatie (2)

A B

A B

A B

Simplex

Half-duplex

Full-duplex

Communicatiekanaal

Parallel versus serieel

Bits per second (bps) vs. Bytes per second (Bps) Baud rate: symbols/sec bps = baud . 2log n (n: number of signal levels)

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

bit rate = 2 x baud rate

Baud rate

Multiplexer Demultiplexer

Multiplexing

TDM versus FDM

Frequency Division Multiplexing

Time Division Multiplexing

Shift register

Data buffer

Serial data

Parallel data

Shift (transmit) clockTc

• Bipolar encoding

• Manchester encoding

Clock extractingreceiver

PLL

Serieel (bit-synchroon)

BI-SYNC protocol

Serieel (frame synchroon)(tijdelijk synchroon)

idle

Shift register

Data buffer

Serial data

Parallel dataStart bit

data bit

data bit

Par bit

Stop bit

trigger samples

Serieel (asynchroon)

data

ready

ready

data

Een strobe is een opgaande of neergaande flank

Parallel (strobe)

REQ

ACK

data

Parallel (handshake)

ready

Ack

data data

ready

Ack

data valid

Parallel (handshake)data staat klaar

Centronics Interface

V.21: 300 bps duplex V.22: 1200 bps duplex V.22bis: 2400 bps duplex V.24: interchange DTE – DCE

(RS232) V.32: 9600 bps duplex V32bis: 14.400 bps duplex V.34: 28.800 bps duplex V.90: 56.600 bps duplex

X.25: The most popular packet-switching protocol for WANs

X.400: The universal protocol for e-mail.

Comité Consultatif International Télégraphique et Téléphonique (CCITT)

Nu: International Telecommunication Union (ITU)

V(oiceband) en X - normen

V.24 - RS-232 (25-polig)

Recommended Standard => EIA-232-DElectronic Industries Alliance

9-polige RS-232 connector

RI = Ring Indicator

DTE DTE

Data Terminal

Equipment

Null Modem

Single-ended

RS-232 signaal

Spraak 4 kHz bandbreedte

(300 - 3400 Hz)

Openbare ‘analoge’ netwerken

Modulatie: AM, FM, PM

DTE DTEDCE DCE

Data Terminal

Equipment

Data Communication

Equipment

V24 of RS 232

V21 … V34

Modem (modulator/demodulator)

(Asymmetric) Digital Subscriber Link

Computer

Modem

Splitter

DSL

DigitalSubscriberLink

5460 m

ADSL Spectrum Fritz!box

Image: Wikipedia

CMTS

CableModemTerminationSystem

Opdrachten

Bestudeer hfdst. 10.1 t/m 10.6 Maak opgaven 10.1 t/m 10.4 en 10.6