1. DATA COMMUNICATION
Lecture-32

2. Recap of Lecture 31 The Telephone System Analog Services
Digital Services
T-Lines

3. Overview of Lecture 32 T-Lines in Analog Transmission
Fractional T-Lines
E-Lines
Fiber To The Curb (FTTC)
Error Detection and Correction

4. T Lines for Analog Transmission
Using PCM and TDM, T lines can be used for analog transmission

5. T Lines for Analog Transmission

6. T1 Frame

7. Fractional T Lines
Allows several subscribers to share one line by multiplexing their transmissions
Their transmissions are interleaved through a device called a DSU/CSU (digital service unit/channel service unit)

8. Fractional T Lines

9. E Lines Europeans use a version of T lines called E lines
Line Rate(Mbps) Voice channels E E E E

10. Digital Signal Service

11. Fiber to the Curb (FTTC)
Devised by telephone and cable TV companies to employ optical fiber while keeping the expense down
From a central office to the curb: optical fiber
From curb to the subscriber premise: twisted-pair or coaxial cable

12. FTTC in the Telephone Network
Twisted-pair is multiplexed in the junction boxes
Optical signals are multiplexed using WDM

13. FTTC in the Telephone Network

14. FTTC in the Cable TV Network
Coaxial cables are multiplexed in the junction box
Optical signals are multiplexed using WDM

15. FTTC in the Cable TV Network

16. Types of Errors
An electromagnetic signal is subject to interference from heat, magnetism, and other forms of electricity
Single-bit error: 0  1 or 1  0
Burst error: Multiple bits are changed

17. Types of Errors

18. Summary T-Lines in Analog Transmission Fractional T-Lines E-Lines
Fiber To The Curb (FTTC)
Error Detection and Correction

19. Suggested Reading Section 8.5, 8.7, 9.1,
“Data Communications and Networking” 2nd Edition by Behrouz A. Forouzan