Phone number validation using VOIP/SIP

The task is to validate an U开发者_运维问答S phone number. Checking format of the number is not enough.

So I should make a call to the number and determine if the subscriber answers.

Is it possible to automate it using VOIP solutions?

Please, suggest any ideas to start with.

I'm going to implement it on Windows platform (probably .NET or Java). It can me for example a console application that receives a parameter (a phone number) and returns true or false.

I would recommend using Twilio (twilio.com) for this. It is a simple to use web application that allows you to build this type of functionality in the cloud. Your system would make an HTTP POST request to initiate the process - and your web server would end up being called with the outcome of the call. Their website provides many examples that would fit what you're looking to do.

Probably you may try to use "options ping" for that (see http://hive1.hive.packetizer.com/users/packetizer/pocs/POCS-1.pdf). I didn't try this myself yet, but in theory, if you try to send an OPTIONS request to device, then you should have 200 or 503 in responce. That means device recieved your packet => device number is valid and route is known. Other responce codes will indicate an error.