Detecting Valid Telephone Numbers

Dear Coders, I need a piece of software/program that will accurately detect if a phone number is valid (operational) by calling this number, check the returned signal and hang up BEFORE THE TELEPHONE ON THE SECOND END ACTUALLY RINGS. I'm looking for disconnected telephones, FAX machines etc. The software should preferably use simple low cost telephony hardware BUT if a special telephony card would be required, is also an option. The system should be able to deal with large quantities of numbers (thousands) and perform the job in a reasonable amount of time. The system should be able to handle MULTIPLE outgoing telephone lines in order to reduce the checking time. The system should work with ISRAEL Telephone infrastructure. So if you need any info about it, ask me. Good Luck! ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform Windows, preferably VB6 or .NET