Defines which days of the month the current time is valid for. It is a sequence of 64 BITS, where each BIT represents a corresponding day of the month in forward or reverse order. Starting from the left-most bit, the first 31 bits identify the day of the month, counting from the beginning of the month. The following 31 bits (bits 32-62) indicate the day of the month, counting from the end of the

month. For months with fewer than 31 days, the bits that correspond to the non-existent days of that month are ignored (e.g., for non-leap year Februarys, bits 29-31 and 60-62 are ignored).

This column evaluates to 'true' if the current day of the month's bit is set.

For example, a value of 0X'80 00 00 01 00 00 00 00' indicates that this column evaluates to true on the first and last days of the month.

The last two bits in the string MUST be zero.