Friday, June 5, 2009

Telecom Time line

In the early years of telecommunications, the only way of linking one telephone with another was by fixed cables. Links between continents relied on cables under the sea. The invention of radio brought the first wireless communications, but because the surface of the Earth is curved these signals could not travel far.
Satellites changed everything. They sit at an exact height above the Earth’s equator (usually around 35,000 km) and they rotate at the same speed as the Earth spins. This means that they stay in a fixed position. Telephone signals can be sent to the satellites and bounced back to Earth. Everywhere on the planet can be covered by only five or six satellites, except for the poles and surrounding areas, which are out of their range.

No comments:

Post a Comment


All data and information provided on this site is for informational purposes only. makes no representations as to accuracy, completeness, currentness, suitability, or validity of any information on this site and will not be liable for any errors, omissions, or delays in this information or any losses, injuries, or damages arising from its display or use. All information is provided on an as-is basis.