Electronic calendar digital frame Most of digital frames come with electronic calendar, however, not every one supports RTC(real time clock) powered calendar, without RTC power, all the calendar adjustment will expire after digital frame users pull off the power adapter.For buyers who really care electronic calendar function,we suggest adding RTC battery to make the calendar recordable. Compared with already matured electronic calendar market, digital frame OEM buyers need to focus on the replacement segment in which people will buy digital frames for the calendar function.