Smartphones are often set apart from their less functional handheld cousins by the type of keyboard. With few exceptions, they have QWERTY-type thumb keyboards with one letter per key. More basic handhelds come with telephone-like numeric keypads that represent at least three letters and a symbol or two. These keypads slow down text entry across the board, but particularly for users who grew up using conventional keyboards.

The drawbacks of the conventional keyboard are size and cost. A full-width keyboard necessitates a full-width form factor that may not always fit easily in a user’s pocket. Earlier BlackBerry devices, for example, were somewhat awkward to use as telephones due to their awkward ergonomics. Conventional numeric telephone keypads give designers the flexibility to create narrower form factors that are easier to carry. They are also less expensive to manufacture, which drives the second issue for vendors: cost.