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 64
21.14

Telephone exchange equipment

banks of switches step to each dialled figure and join the call without an operator

KnowledgeYear 64Stands on 293 earlier

AWhat it needs

Needs 293 other products in all, 5 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.