Codes
What are codes?: Changing information from one type to another is known as encoding (or putting it into code). You can encode a message as Semaphore using flags. In a way, the human voice is encoded before we speak because the air we use changes as it passes through our vocal cords.
Telephone numbers
The first telephones: In 1879, the first telephone exchange opened in Britain. There were only eight users with phones, and calls were connected by people called operators. They plugged and unplugged wires to join the different phone lines together. There were no telephone numbers then - people just told the operator who they wanted to call.
Numbers in code
Morse code: Before the telephone was invented, the telegraph was used to send messages over long distances. Early telegraphs could only send pulses of electricity along a wire, not actual messages. In 1840, Samuel Morse and Alfred Vail invented a code to translate these pulses into letters and numbers, called Morse code. For example, in Morse code, the letter A is represented by a short then a long pulse of electricity. This can be written as dot dash or .
Communications Project Primary: Teacher's notes : Communicating with numbers
