1csnw1 – week 3 datacommunicatie. datacommunicatie? communications men string telephone wire on an...
TRANSCRIPT
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