Add TouchTone Typing to Your Next Project

The Blackberry made phones with real keyboards popular, and smartphones with touch keyboards made that input method the default. However, the old flip phone crowd had just a few telephone …read more

Jun 24, 2025 - 11:20

Add TouchTone Typing to Your Next Project

The Blackberry made phones with real keyboards popular, and smartphones with touch keyboards made that input method the default. However, the old flip phone crowd had just a few telephone keys to work with. If you have a key-limited project, maybe check out the libt9 library from [FoxMoss].

There were two methods for using these limited keyboards, both of which relied on the letters above a phone key’s number. For example, the number 2 should have “ABC” above it, or, sometimes, below it.

In one scheme, you’d press the two key multiple times quickly to get the letter you wanted. One press was ‘2’ while two rapid presses made up ‘A.’ If you waited too long, you were entering the next letter (so pressing two, pausing, and pressing it again would give you ’22’ instead of ‘A’).

That’s a pain, as you might imagine. The T9 system was a bit better. It “knows” about words. So if you press, for example, ‘843’ it knows you probably meant ‘the,’ a common word. That’s better than ‘884444333’ or, if the digit is last in the rotation, ‘844433.’ Of course, that assumes you are using one of the 75,000 or so words the library knows about.

If you just want to try it, there’s a website. Now imagine writing an entire text message or e-mail like that.

Of course, there’s the Blueberry, if you really want physicality. We love that old Blackberry keyboard.