2 LAN WAN

D. PSTNCellular NetworkGSM

Voice Communication -> -> (Transmitter)(Receiver) Transmitter Diaphragm Diaphragm

ReceiverTransmitterTelephone Networks : Demo

A simple telephone

A "real" telephone

The Analog Local Loop

(CPE) , (Transmission Media ) , (Switching System) (PSTN)

Dual Tone (,, 1112 1900-xxx-xxx)

PSTNPublic Switched Telephone Network -> PSTN PBXCircuit SwitchingSONET/SDH

PBXPrivate Branch Exchange PABX (Private Automatic Branch Exchange )

Circuit Switching end-to-end

Circuit Switching

SONET/SDHSynchronous Optical Network Synchronous Digital Hierarchy 51Mbps 40Gbps Telephone Switch

SONET/SDH

SONET/SDH

CTI Computer Telephony IntegrationCall Center headset

VoIP SoftPhone ATA (Analog Telephone Adapter) IP Phone IP Packet

Cellular Network

cell Frequency Reuse cell cell

Every cellular system digital or analog is comprised of four parts.

1 ) Cells and cell sites ( base stations )

2 ) Switching station ( mobile telephone switching office or MTSO )

3 ) System operator and its local office

4 ) Cellular telephones

Mobile Unit Initialization - Originated Call - Paging MTSO- Call Accepted - Ongoing Call - Handoff -

Mobile BTS 2 Control ChannelTraffic Channel

GSM

GSM Global System for Mobile Communication 1980 900 Mhz 1.8 GHz 1.9 GHz 2 GSM 850/900 1 GSM 1800/1900 SMS,MMS,GPRS,EDGE

GSM - GPRSGPRS General Packet Radio Service (wireless) - 171.2 kbps package Internet GPRS GPRS 8 (6 , 2 ) GPRS - Always On - Video - MMS - GSM - - PDA, - Notebook

First Generation(1G)1970/ 15 KbpsSecond Generation(2G)1990 cell GSM/ 115 Kbps ( 40Kbps)Third Generation(3G)400Kbps 1MbpsFourth Generation(4G)