The validity period refers to the period of time during which the opened calling card can be used normally from the date of activation. The expiration date is the date on which the opened calling card ceases to be valid. The validity period of the calling card is a period of time, such as the production date is 2014-08-27, the expiration date is 2015-08-27, and the activation date is also 2014-08-27. The activation date is automatically generated when the card is used, and is not editable. The validity period is 2 days, which means that the opened calling card can be used for 2 days after it is activated in 2014-08-27, and will not be used after 2014-08-29. If it is not enabled for a long time, it cannot be enabled after the expiration date is 2015-08-27.
When the validity period is 0, when the calling card is enabled, when the expiration date is small, the expiration date of the account is displayed as the expiration date; when the expiration period is large, it is greater than the setting in the system parameters (after the account recharge is successful, the validity period is 1) -3650), calculated by system parameters.