Getting caller phone number without for caller to pay fees

Hi all,

We need to build a server in order to retrieve the phone number of callers, without opening the line and hanging up.
The use case is:

  • the caller calls a phone number just to notify the server about something
  • the line is cut by the server upon the call reception (important: without for the caller to pay anything).
  • the server records the caller phone and the date of the call in database.
    End of use case.

Can that be done with an Asterisk analog card?
Must I buy a digital card?
Is there a VoIP based solution that can prevent me from buying a digital card?

Thank you for your help

All of these are possible and should be the natural result of simple dialplans.

However, your PSTN operator or SIP gateway operator may well consider this a breach of their fair use policies, as it is clearly denying them the revenue needed to operate their services.