Letters are represented by one or more presses of the same key depending on their order listed on the button. e.g. Press 5 key once for J, twice for K, thrice for L.

To specify a digit use the number of letters listed on the button plus one. e.g. Press 5 key four times to get digit 5. When two characters in a row use the same key, use the "A" key as a separator.

Digits are represented by a single key press.

Letters (or space) are represented by the corresponding key followed by A, B, C, or D depending on the order of the letter in the order listed.