Cellular Digital Accessory

The Cellular Digital Accessory (CDA) number identifies the software version and customization of a Mobile phone.Customization, among others, relates to operator-customized startup and shutdown videos, user greeting, web browser's home page and preinstalled bookmarks and also language packs that come preinstalled with the phone. CDA version depends on the country of purchase as well as on the network operator.
See more at Wikipedia.org...