code: public final void setDateTimeFlag(int field, boolean value)
  	{
  		if (field == CLOCK_SYNC) {
  			setBitEx(0, QUALITY, value);
  			return;
  		}
  		final int f = field - WORKDAY;
  		if (f < 0 || f >= FLAG_MASKS.length)
  			throw new KNXIllegalArgumentException("illegal field");
  		setBit(0, FLAG_MASKS[f], value);
  	}
docs: Sets date/time information for the given field of the first date/time item.
  <p>
  Allowed fields are {@link #CLOCK_FAULT}, {@link #CLOCK_SYNC}, {@link #WORKDAY}
  and {@link #DAYLIGHT}.<br>
  This method does not reset other item data or discard other translation items.
  
  @param field field number
  @param value <code>true</code> to set the information flag, <code>false</code>
  to clear