--- title: "Digital vs manual switching; evolution in Nepal" subject: "Telecommunications" chapter: 1 key: "semester_8/telecommunications:digital-vs-manual-nepal-evolution" source: https://www.bctengineer.com/q/semester_8/telecommunications/digital-vs-manual-nepal-evolution site: BCT Engineering --- # Digital vs manual switching; evolution in Nepal Telecommunications · Chapter 1: Telecommunication Networks - Asked in: 2075 Asoj, 4+4 marks - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_8/telecommunications/digital-vs-manual-nepal-evolution - Whole chapter: https://www.bctengineer.com/md/semester_8/telecommunications/chapter-1 ## Question Why digital switching system is preferred over manual switching system? Briefly explain evolution of telecommunication in context of 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. ## Answer #### 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. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Why does digital switching give better quality? A. PCM signals are regenerated so noise does not build up B. It adds analogue noise C. Operators fix the noise D. It uses longer cords Answer: A. Regeneration prevents noise accumulation. (Key point: Quality) 2. Digital exchange capacity compared with manual board A. A few hundred versus tens of thousands B. Tens of thousands of lines versus a few hundred C. Equal D. Always 100 lines Answer: B. Digital exchanges are far larger. (Key point: Capacity) 3. Maintenance in digital exchanges is A. Manual cord checking B. Not needed C. Self-diagnosis and remote O&M D. Done by operators Answer: C. Software supports remote O&M. (Key point: Maintenance) 4. Which came first in Nepal? A. GSM 1999 before NTC B. Ncell before the Telecom Act C. 4G before 3G D. NTC in 1975, before the Sanga earth station in 1982 Answer: D. Order: 1975 NTC, 1982 Sanga, 1999 GSM, 2005 Ncell. (Key point: Nepal 1975) ## Related in Telecommunications - [Evolution of telecommunication and switching systems](https://www.bctengineer.com/question.md?key=semester_8%2Ftelecommunications%3Aevolution-telecom-switching) — Telecommunications, chapter 1, asked 3× - [Digital switching system and its functions](https://www.bctengineer.com/question.md?key=semester_8%2Ftelecommunications%3Adigital-switching-functions) — Telecommunications, chapter 4 - [Milestones in the evolution of telecommunication](https://www.bctengineer.com/question.md?key=semester_8%2Ftelecommunications%3Aevolution-of-telecommunication) — Telecommunications, chapter 1, asked 2× - [Exchange roles and demerits of manual switching](https://www.bctengineer.com/question.md?key=semester_8%2Ftelecommunications%3Aexchange-roles-manual-demerits) — Telecommunications, chapter 1 - [Switching hierarchy and evolution until the telephone](https://www.bctengineer.com/question.md?key=semester_8%2Ftelecommunications%3Aswitching-hierarchy-telephone-evolution) — Telecommunications, chapter 1, asked 3× - [Telecommunication definition and Nepal's history since 1913](https://www.bctengineer.com/question.md?key=semester_8%2Ftelecommunications%3Atelecom-nepal-history-1913) — Telecommunications, chapter 1, asked 2× ## Related in other subjects - [Context switching; distributed vs network OS](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Acontext-switch-dos) — Distributed System, chapter 3 - [Process vs thread; context switching](https://www.bctengineer.com/question.md?key=semester_6%2Foperating_system%3Athread-context-switching) — Operating System, chapter 2 - [Context switching in RTOS](https://www.bctengineer.com/question.md?key=semester_6%2Fembedded_system%3Acontext-switching) — Embedded System, chapter 6, asked 3× - [Context switching, 5-state model, MLFQ](https://www.bctengineer.com/question.md?key=semester_6%2Foperating_system%3Acontext-switch-5state-mlfq) — Operating System, chapter 2