pool and the temporary pool are all available for each subscriber thus a subscriber 39 s limit is simply the number of numbers in the pools the numbers in the pools or pool although all available for each subscriber are a finite resource and a subscriber could exhaust such a resource the action taken in such a case is dictated by operator policy return call allowed a called party can request via a self management interface such as a web gui or an sms command which could be a reply to an u2018 anonymous call notification u2019 message that a request be made to the calling party that the called party be allowed to return a call to the calling party on such a request an sms could be sent to the calling party requesting authorization to do this if the calling party replies in this embodiment with an affirmative sms the return call allowed field is set appropriately and the called party is informed via sms that their request is successfully completed the called party can then initiate a call to the calling party note the distinction from the return call allowed field in the subscriber settings table which can be viewed as permanent as it does not have an expiry time explicitly defined whereas in the pending call database the return call allowed setting will expire according to the expiration time pending call aging this component autonomously ages entries in the pending call database that have exceeded the configured validity period command handler this component interprets commands returned in messages or forwards the messages if they do not contain a command in the case of.