In order for you to make a call, the central switch needs to know the number you want to reach. The switch is, in essence, a great big computer. Like any computer, it doesn't understand English, so you need to give it the number in a form it can understand. There are two common ways of doing this: tones and pulses.

Tone dialling is now the most common form. A touchtone phone has a tone generator built into it. When you press a key on the phone's keypad, you will hear a beep. This sound is created by combining two tones (for example, 697Hz and 1209Hz is phone speak for '1').

Pulse dialling is the old method. When telephones had dials rather than keypads, the dial generated electrical pulses in the wire to transmit the number to the exchange. In New Zealand, to dial '1', you would rotate the dial almost as far as it would go, and it would click back, generating 9 pulses. This is why the emergency number in New Zealand is 111. Not only is it easy to remember, but if the insulation on phone wiring became worn, it would take 27 sparks within 30 seconds to generate a false emergency call. So false emergency calls were unlikely to happen.

Your phone is almost certainly a touch tone phone. If you are unsure, hold the receiver up to your ear and press a key. If you hear a beep, it is a touch tone phone. If you hear a series of clicks, or if it has a dial rather than a keypad, it is a pulse phone. Pulse phones will not work on our network.