# [TECH] Telegraph & Telephone

**The Telegraph** (Morse, 1837) and **Telephone** (Bell, 1876) were the first technologies to transmit information electronically, creating the global telecommunications infrastructure.

## Overview

Samuel Morse's electromagnetic telegraph (1837) and the transatlantic cable (1866) allowed near-instantaneous communication across continents for the first time, revolutionising commerce, diplomacy, and news. Alexander Graham Bell's telephone (1876) extended this to voice, creating the public switched telephone network (PSTN) that served as the backbone for all subsequent communications infrastructure.

The Bell System (AT&T/Bell Labs) became one of the most productive R&D institutions in history, producing information theory (Shannon, 1948), the transistor (1947), the laser, Unix, and C. The telephone network infrastructure directly enabled the Internet.

## Key Actors

- **Companies**: Western Union (1851), AT&T/Bell System (1877–1984), Western Electric, Siemens
- **Inventors**: Samuel Morse (1791–1872), Alexander Graham Bell (1847–1922), Elisha Gray (1835–1901)

## Key Patents

- Bell, A.G. US Patent 174,465 (1876) — telephone (one of the most litigated in history)
- Morse, S. US Patent 1,647 (1840) — telegraph

## Economic Value

Global telecommunications market: **\$1.7 trillion/year** (2023, Statista). The telephone system laid the physical and institutional infrastructure for the internet, which contributes ~\$11T/year to global GDP.

## Notes

Telecommunications market from ITU 2023 report. The enabling value for internet infrastructure is estimated by McKinsey Global Institute (2011, 2023).

## What This Enables
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- **[TECH] Radio & Wireless Communication** — Wireless telegraphy was the direct wireless extension of the wire telegraph, using the same Morse code.
- **[SCI] Information Theory** — Shannon worked at Bell Labs on maximising information throughput of telephone and telegraph channels.
- **[TECH] Vacuum Tube Electronics** — Long-distance telephone repeaters (triode amplifiers) were the first major commercial application of vacuum tubes.
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# Parents

* [SCI] Classical Electromagnetism
* [SCI] Classical Electromagnetism