Such a keypad can be also used for text entry. Each key typically has 3-4 letters on it. Predictive text entry is usually used to speed this process. See: Predictive Text Entry Phones designed for ...

A standard phone keypad consisting of the numbers from 0 ... They include alphabet characters - usually several letters are assigned to each of the numeric keys - and you can toggle their input ...

sitting on the back of the smartphone such that you hold the phone much as you often normally would. Another is that it plugs in just like any other USB keyboard. And the last should make any vi ...