1. Introduction to Telecommunications

2. Topics to be discussed Type of connections
Electromagnetic spectrum and bandwidth
Analog and digital transmission
Multiplexing
Transmission media

3. Types of connections Switched network connections
Leased line network connections
Dedicated network connections

4. Signals Analog signal Digital signals Amplitude Phase Frequency 1 or 0
digital signal = f + f3 + f5 +f7 +f9 +f11 +f f(infinity)
Analog signal
Amplitude
Phase
Frequency
Digital signals
1 or 0

5. Bandwidth
The range of frequencies that made up a signal is known as bandwidth.
Narrow band – DS-0 at 64 Kbps
Wideband – n×DS-0 for T-carrier, E-Carrier and J-Carrier up to 45 Mbps
Broadband – anything over 2Mbps
Fiber optic
Speed 10Gbps – 32 volumes of Encyclopedia Britannica in 1/10 seconds
Synchronous Optical Networking (SONET) and Synchronous Digital Hierarchy (SDH) - started from 51Mbps

6. Analog and Digital Signal Transmission
Maximum data rate – 33.6Kbps
AM, FM, PM
Digital
Analog digitizes through 56Kbps Modem
ASK, FSK, PSK
Regenerative repeaters – drop and hub repeaters

7. Analog to Digital Conversion
Figure: ISDN telephone
Codec
8 bit PCM for PSTN
Both coding and compression for cellular network
Modem
Household Modem – 56Kbps
Via co-axial cable
Digital
ISDN Modem – for voice, video or data at high speed
ADSL Modem
Telephone line
Can integrate with wireless access point
Fiber optic Modem
Can come through a combination of Wireless Modem/router
Figure: DSL router
Figure: Fiber Optic
endpoint at customer premises

8. Multiplexing DS0 DS1 64Kbps data rate
8kHz sampling rate at 8bits/s for each voice channel.
DS1
A communication protocol
Multiplex 24 voice channels
1.544 Mbps

9. Multiplexing Additional benefits Data compression
Error detection and correction
To ensure integrity and accuracy
Manage resources for transmission
Disaster management
Prioritize
Provide efficient use of leased line

10. Multiplexing FDM TDM Statistical TDM (STDM) CDMA WDM Dense WDM (DWDM)
Usually analog
Radio
Cable TV through coaxial cable
TDM
Statistical TDM (STDM)
CDMA
WDM
Dense WDM (DWDM)
Coarse WDM (CWDM)

11. Traditional Transmission Media
Wired
Twisted pair
Coaxial cable
Fiber optic cable
Wireless
Networks
802.11g
Wi-Fi
Li-Fi