- 2075 Asoj · 4+4 marks
Digital vs manual switching; evolution in Nepal
Short answer
Digital switching is preferred because it is automatic, fast, private, error-free, higher capacity, lower running cost, supports advanced services, and regenerates PCM signals without noise. Nepal evolution: 1913 first telephone, 1935 manual exchange, 1962 automatic exchange, 1975 NTC, 1982 Sanga earth station, 1997 Act, 1999 GSM, 2004 Nepal Telecom, 2005 private GSM, 2007 3G, 2017 4G.
Why digital switching system is preferred over manual switching system? Briefly explain evolution of telecommunication in context of Nepal.
Why digital switching is preferred over manual switching
| Point | Manual switching | Digital switching |
|---|---|---|
| Call set-up | Slow, by operator | Very fast, automatic |
| Privacy | Operator hears calls | Full privacy |
| Errors | Human errors | Very low error rate |
| Capacity | Few hundred lines per board | Tens of thousands of lines |
| Running cost | Many operators | Low; few maintenance staff |
| Services | Basic calls only | Call waiting, forwarding, conference, CLI, ISDN, data |
| Quality | Analogue, noise added | Digital PCM, regenerated, no noise build-up |
| Size/power | Large boards | Compact ICs, low power |
| Maintenance | Manual | Self-diagnosis, remote O&M |
| Integration | None | Works directly with digital trunks, SS7, billing |
Digital (SPC, time-division) exchanges are also cheaper per line, easy to expand by software and support automatic billing.
Evolution of telecommunication in Nepal
- 1913 AD: first telephone line in Kathmandu for the Rana rulers.
- 1935: manual exchange of about 100 lines in Kathmandu.
- 1950s: HF radio links; public telephone service begins.
- 1962: first automatic exchange (about 1,000 lines) in Kathmandu.
- 1975: Nepal Telecommunications Corporation (NTC) formed.
- 1982: satellite earth station at Sanga for international service.
- 1980s–90s: digital exchanges and microwave backbone across the country.
- 1997–98: Telecommunication Act 2053; Nepal Telecommunications Authority set up; private operators allowed.
- 1999: GSM mobile by NTC; 2004: Nepal Doorsanchar Company Ltd (Nepal Telecom); 2005: private GSM (now Ncell).
- 2007 onward: 3G (2007), 4G LTE (2017), national optical fibre backbone, FTTH broadband and mobile Internet reaching most of the country.
✓ Answer checked by Claude Opus 5.5 (high effort)
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