Assigning Keys to Letters in Persian key boards

Standardizing Persian alphabet letters in PCs، note books and cell phones is an important issue in Persian writing. Diversity of letters assigned to a given key as well as inappropriateness of the assigned letters to keys in relation to the frequency of letters are the most important issues for the Iranians using Persian keyboards. Although the standard Persian keyboard has been organized in a way that all similar letters stand side by side and they have almost been organized alphabetically، the most and the least frequent letters are not the most and the least accessible ones. To assign letters to keys، the researcher calculated the frequency of Persian letters in a corpus of about 1،270،000 letters. The results showed that there is no significant relationship between the frequency of the letters and the accessibility of the keys assigned to them. The study analyzed the keys organized in each of three rows on the Persian keyboards based on the frequency of letters assigned to them. It was found out that the letters with a high degree of frequency stand close to the letters with low frequency. The researcher designed a keyboard layout based on relative frequency of letters and fingering frequency.