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Milestones in the evolution of telecommunication
Short answer
Major milestones: optical telegraph (1790s), electric telegraph (1837), telephone (1876), manual exchange (1878), Strowger automatic exchange (1892), transistor (1947), SPC electronic exchange (1965), digital switching (1970s), GSM (1991), and 4G/5G mobile broadband.
Explain the evolution of Telecommunication. Describe briefly the major milestones in the evolution of telecommunication.
Telecommunication evolved gradually: each new system grew out of the limits of the previous one, moving from visual and electrical signalling to voice, then to automatic switching, radio, digital and finally packet/IP and mobile networks.
Major milestones
| Year | Milestone |
|---|---|
| 1790s | Optical (semaphore) telegraph of Chappe, France |
| 1837–44 | Electric telegraph and Morse code (Morse, Cooke & Wheatstone) |
| 1866 | Successful transatlantic telegraph cable |
| 1876 | Telephone invented by A. G. Bell |
| 1878 | First manual telephone exchange, New Haven (USA) |
| 1889–92 | Strowger automatic step-by-step exchange (La Porte, 1892) |
| 1895–1901 | Marconi's wireless telegraphy; transatlantic radio (1901) |
| 1906 | Triode valve (De Forest); amplifiers make long lines possible |
| 1920s–30s | Crossbar switch, carrier (FDM) multiplexing, coaxial cable |
| 1937 | Pulse code modulation (Reeves) |
| 1947 | Transistor invented (Bell Labs) |
| 1956 | First transatlantic telephone cable (TAT-1) |
| 1962 | Telstar satellite; T1 PCM carrier systems |
| 1965 | No. 1 ESS – first stored program control exchange |
| 1970 | Low-loss optical fibre (Corning); E10 digital exchange |
| 1976 | No. 4 ESS digital toll switch; CCITT SS7 later |
| 1979–83 | First cellular networks (1G: NTT, AMPS) |
| 1980s | ISDN; TCP/IP adopted on ARPANET (1983) |
| 1991 | GSM (2G digital mobile); World Wide Web |
| 2001 | 3G (UMTS) |
| 2009–10 | 4G LTE |
| 2019 | 5G deployment |
Main trends
- Manual → automatic: operators replaced by Strowger, crossbar and then computer-controlled (SPC) exchanges.
- Analogue → digital: PCM, TDM and digital switching gave better quality and integration of voice and data.
- Copper → fibre and radio: higher bandwidth and lower loss; satellites and microwave for long distance.
- Fixed → mobile: cellular networks from 1G to 5G.
- Circuit → packet: Internet, VoIP and all-IP networks.
Each milestone increased capacity and quality and lowered cost, which is why telecom is called an evolutionary process.
✓ Answer checked by Claude Opus 5.5 (high effort)
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