Civilization manualBook 1: From Bare Hands to Steam and Electricity765 entries · 23 phases · 100 years
The Island
Phase 21 — Microphone, speaker, magnetic tape and the telephone exchange  /  About year 61
21.08

Long-distance line with valve repeaters

an amplifier every few miles carries a voice the length of the island

KnowledgeYear 61Stands on 295 earlier

AWhat it needs

Needs 295 other products in all, 2 of them directly.

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