T-Carrier vs E-Carrier

T-CARRIER VS E-CARRIER

System Basics

E1 :

• 32 voice time slots x 8 bits per slots = 256 bits
• Number of bits per frame : 256 bits/frame
• The E1 bit rate : 8000 frames/second x 256 bits/frame = 2.048Mbps

E2 :

• Total bits : 256 bits
• Number of bits per frame : 256 x 4 + 32 = 1056 bits
• The T2 bit rate : 1056 bits/frame x 8000 frames/second = 8.448Mbps

E3:

• Total bits : 1056 bits
• Number of bits per frame : 1056 x 4 + 72 = 4296 bits
• The T2 bit rate : 4296 bits/frame x 8000 frames/second = 34.368Mbps

Digital Hierarchy

• Bandwidth : 2.048 Mbps (Full Duplex)
• 32 Channels
• Signaling
• Controlling
• Pulse Code Modulation
• Connect PABX, CO or main exchange
• Physical characteristic of transmission path
• Physical layer (layer 1)
• ATM and others form layer 2 (able to pass over E1 lines)
• Operates over 2 seperate sets of wire
• Unshielded twisted pair (Balanced)
• Coaxial Cable (Unbalanced)

Frame Format

E-Carrier

Frame Format

• System Basics
• Digital Hierarchy
• Frame Format

• TS0
• Synchronization, alarms and messages
• Reserved for framing (transmits fixed pattern)
• Full Cyclic Redundacy Check
• TS1 - TS15
• carry user data
• TS16
• carry signaling data
• Channel Associated Signaling (CAS)
• Common Channel Signaling (CCS)
• Signaling System 7 (SS7)
• may carry data
• TS17 - TS31
• carry user data

T1 or DS1 (digital signaling 1) :

• 24 voice time slots x 8 bits per slots = 192 bits
• Number of bits per frame : 192 bits + I framing bit = 193 bits/frame
• The T1 bit rate : 8000 frames/second x 193 bits/frame = 1.544Mbps

T2 or DS2 (digital signaling 2) :

• Total bits : 193 bits
• Number of bits per frame : 193 x 4 + 17 = 789 bits
• The T2 bit rate : 789 bits/frame x 8000 frames/second = 6.312Mbps

T3 or DS3 (digital signaling 3) :

• Total bits : 789 bits
• Number of bits per frame : 789 x 7 + 69 = 5592 bits
• The T3 bit rate : 5592 bits/frame x 8000 frames/second = 44.736Mbps

T-Carrier

T-Carrier vs E-Carrier

• System Basics
• Digital Hierarchy
• Frame Format

Comparison between T1 & E1

by

Noramirah binti Mohd Suki

Chwee Jian Thong

Chew Hao Chen

Digital Hierarchy

System Basics

History of

T-Carrier and E-Carrier

• Full duplex
• Digital
• Four wire circuit
• two pairs of unshielded twisted copper wires, fiber optic media
• Time-division multiplexing
• Pulse code modulation
• Bipolar format
• alternate mark inversion (AMI)
• Byte synchronous transmission
• bipolar 8 zero substitution (B8ZS)
• Versatility

Scope of Discussion

• History of T-Carrier and E-Carrier
• T-Carrier
• E-Carrier
• Comparison between T-Carrier & E-Carrier
• Conclusion

Conclusion

History of E-Carrier

History of T-Carrier

• The European Conference of Postal and Telecommunications Administrations (CEPT) revised and improved the T-carrier and standardized the E-carrier system
• Widely used in Europe country
• Developed in the 1970s and widely available in the 1980s
• Graded E1, E2 and so on in order of increasing transmission speeds

• End of World War II, increasing demand of telephone voice traffic
• AT&T faced problem with expensive FDM technology
• Combination of TDM & PCM in a system solved the problem
• Bell Labs developed the system and named it as T-Carrier in 1962
• Mainly used in North America, South Korea and Kyoto
• First T-carrier system: T-1
• Existence of other T-carrier system:

- Multiples of T-1 such as T-2, T-3 and T-4

- Fractional T-1 circuits

E-carrier is the improve version of T-carrier. Higher quality of transmission can be achieved using E-carrier system. It can be prove by comparing the characteristics between both carriers; length of a time slot, bit rate of TDM signal, type encoding/decoding, number of time slots per frame etc.

References

• http://www.ad-net.com.tw/index.php?id=500
• http://www.princeton.edu/~achaney/tmve/wiki100k/docs/E-carrier.html
• http://www.radio-electronics.com/info/telecommunications_networks/e-carrier/e-carrier-system.php
• http://www.techfest.com/networking/wan/tcarrier.htm
• http://searchtelecom.techtarget.com/definition/T-carrier-system
• http://en.wikipedia.org/wiki/T-carrier
• http://www.comsoc.org/files/Publications/Magazines/ci/hist-comm/2011-apr.pdf