Startup Idea: Call Filter Software for Computer Support

Startup idea to develop a software that can filter incoming calls based on a provided pin. This program would ideally be able to intercept the call, listen to dial tones, request for a pin, and reroute the call upon failure to provide correct pin.

I work in computer support.

Daily I have to filter through people contacting me for issues I am not currently supporting.

I would possibly pay for software that would accomplish the goal below.

A program that filters phone calls, by requesting a providing pin before they are actually routed to my phone. If they cannot provide the pin, or fail, I would like that call redirected.

Using a PC to receive the call first, something like Skype, that can listen to dial tones and forward the call based on set logic. None.