Multi-tapping is an older procedure used to enter text using a telephone keypad. You tap (press) a key a certain number of times to select a letter from the ones associated with a particular key. For example, the letters A, B, and C are associated with the 2 key. Tapping the key once enters an "A," twice enters a "B," and three times enters a "C." Although multi-tapping is workable, it is also a bit cumbersome in practice, and a number of alternatives have been developed. The Fastap keypad is a miniature alphanumeric keypad for use with mobile phones. Another widely-implemented approach, text on nine keys (T9) uses predictive software that allows you to tap a key only once for each letter. T9 makes informed guesses about what text you intend to enter, based on the likelihood of letter combinations.

This was last updated in September 2005

Dig Deeper on Mobile and wireless network technology