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 70
21.19

Magnetic tape

a plastic ribbon coated with fine iron oxide holds sound as a pattern of magnetism

MakingYear 70Stands on 250 earlier

AWhat it needs

Needs 250 other products in all, 2 of them directly.

View

Open a box to see what it needs. A dashed box is a product already drawn in full: click it to jump there. In the org chart, drag to move around.

The step-by-step procedure for this entry has not been written yet.