MOBILE COMMUNICATIONS

Mobile communications allows direct radio contact with people on the move, connecting them immediately, even in an emergency. Radio was originally invented more than a century ago as a way of communicating with ships. Transistors and microchips now make it possible to get powerful radio equipment into cars and small boats. Unlike a MOBILE PHONE, mobile communication does not rely on the fixed telephone network.

EMERGENCY SERVICES

Fire, police, and ambulance services all have their own radio networks. Some can handle data, such as maps, as well as speech. Messages are sent out from a central transmitter to several vehicles, all of which use one channel to reply – so communications have to be short, and are not private.

MOBILE PHONES

Mobile phones use radio and landlines to transmit calls. A call is picked up by a nearby base station, which passes the call through landlines to another base station or to a fixed telephone. Base stations are low-powered, so they do not interfere with each other, allowing millions of people to talk using only a few frequencies.

MINIATURE MIRACLE

A pocket-sized mobile phone contains more than one computer as well as a microwave radio transmitter and receiver. When you switch it on, the phone finds the nearest base station and logs on so that the system knows where it is. If you start to move out of range, the phone finds another base station and, if necessary, retunes itself.

Copyright © 2007 Dorling Kindersley

stay connected

Sign up for our free email newsletters and receive the latest advice and information on all things parenting.

Enter your email address to sign up or manage your account.

Facebook icon Twitter icon Follow Us on Pinterest

editor’s picks

highlights

12 Pumpkin Activities and Crafts for Kids
Pumpkins and gourds are perfect for fall fun and games with the kids. Find the best pumpkin activities, crafts, printables, and recipes to enjoy with your children this Halloween season.

Kindergarten Readiness App Wins Gold
Our Kindergarten Readiness app won the Gold Award of Excellence in the educational category at the 2014 Communicator Awards. This valuable checklist comes with games and activities to help your child practice the essential skills she needs for kindergarten. Download the Kindergarten Readiness app today!

15 Best Slow Cooker Meals
Too busy to cook? Try one of these deliciously easy slow cooker meals and have dinner waiting when you get home!

Find Today's Newest & Best Children's Books!
Looking for newly released books for your child? Try our new Book Finder tool to search for new books by age, type, and theme, and create reading lists for kids!