TRUYỀN SỐ LIỆU VÀ MẠNG Ch01 transmission media and phy layer

1

Telecomm. Dept.

Faculty of EEE

DCN

HCMUT

Data Communication and

Networking

Dr. –Ing. Vo Que Son

Email: [email protected]

2

Telecomm. Dept.

Faculty of EEE

DCN

HCMUT

Content

Chapter 1: Transmission Media and PHY Layer

Wired and Wireless Media

Physical layer standards: RS232, RS422, RS485

Line Coding

Digital modulation/demodulation

Channel parameters

Gaussian noise and BER

Chapter 2: Data Communication

Asynchronous data transmission

Synchronous data transmission

Channel Coding

Data Compression

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Telecomm. Dept.

Faculty of EEE

DCN

HCMUT

Wired Media

 Guided Media

 How can signal be transmitted in wired media

(cables)?

 Voltage is sometimes referred to as electromotive

force (EMF).

 EMF is related to an electrical force, or pressure,

that occurs when electrons and protons are

separated

Force within a atom

Static Electricity

Electrostatic discharge

neutron

proton

4

Telecomm. Dept.

Faculty of EEE

DCN

HCMUT

Waves

Sine Wave Square Wave

• Repeat the same pattern at

regular intervals

• Continuous voltage

• occur naturally and change

regularly over time

• Repeat the same pattern at regular

intervals.

•do not continuously voltage.

• Repeat the flat pattern on both the

top and bottom of the wave

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Telecomm. Dept.

Faculty of EEE

DCN

HCMUT

Two-wire open lines

Used in short distance communication with low data

rates

Simple structure

Data rate < 19Kbps, max distance L<50m

Sensitive with Crosstalk

Sensitive with EMI

6

Telecomm. Dept.

Faculty of EEE

DCN

HCMUT

Twisted-Pair Cable

Used in LAN and

Telephone networks

Data or voice transmission

UTP, STP, ScTP

Reduce more EMI than

two-wire open lines?

Reduce Crosstalk?

Introduce Skew: delay in

video transmission

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Telecomm. Dept.

Faculty of EEE

DCN

HCMUT

Noise cancellation

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Telecomm. Dept.

Faculty of EEE

DCN

HCMUT

UTP - Unshield Twisted Pair

 Intrinsic Impedance: 100 Ohm

 BW: depending on CAT

 Speed: 10,100, 1000 Mbps depending on cable

quality/category

 Average $ per node: less expensive

 Maximum cable length: 100m

 Media and connector size: small

9

Telecomm. Dept.

Faculty of EEE

DCN

HCMUT

STP - Shield Twisted Pair

Intrinsic Impedance: usually 150 Ohm

Speed: 10,100 Mbps depending on cable

quality/category

Average $ per node: moderately expensive

Maximum cable length: 100m

Media and connector size: medium to large

10 Telecomm. Dept.

Faculty of EEE

DCN

HCMUT

ScTP - Screen Twisted Pair

Intrinsic Impedance: usually 100 Ohm

Speed: 10,100, 1000 Mbps depending on cable

quality/category

Average $ per node: less expensive

Maximum cable length: 100m

Media and connector size: small

11 Telecomm. Dept.

Faculty of EEE

DCN

HCMUT

Most of common cables

Name Type Bandwidth Applications

Level 1 0.4 MHz Telephone and modem lines

Level 2 4 MHz Older terminal systems, e.g. IBM 3270

Cat3 UTP 16 MHz 10BASE-T and 100BASE-T4 Ethernet

Cat4 UTP 20 MHz 16 Mbit/s Token Ring

Cat5 UTP 100 MHz 100BASE-TX & 1000BASE-T Ethernet

Cat5e UTP 100 MHz 100BASE-TX & 1000BASE-T Ethernet

Cat6 UTP 250 MHz 10GBASE-T Ethernet

Cat6a 500 MHz 10GBASE-T Ethernet

Class F S/FTP 600 MHz Telephone, CCTV, 1000BASE-TX in the

same cable. 10GBASE-T Ethernet.

Class Fa 1000 MHz Telephone, CATV, 1000BASE-TX in the same

cable. 10GBASE-T Ethernet.

12 Telecomm. Dept.

Faculty of EEE

DCN

HCMUT

Cable and connectors

13 Telecomm. Dept.

Faculty of EEE

DCN

HCMUT

Cabling Types

 Switch to router

 Switch to PC or server

 Hub to PC or server

 Switch to switch

 Switch to hub

 Hub to hub

 Router to router

 PC to PC

 Router to PC

14 Telecomm. Dept.

Faculty of EEE

DCN

HCMUT

Co-axial Cable

Speed: 10-100 Mbps

Average $ per node:

inexpensive

Media and connector size:

medium

Max cable length: 500m