From Bob Day:
Call Screener is a software application that blocks unwanted phone calls on a landline phone. It runs under either 64-bit or 32-bit Windows 7. Call Screener requires a dial-up modem that has voice and caller ID capability to be installed on your computer. (Call Screener uses only the voice and caller ID features of the modem -- there is no need to "dial-up" anywhere.) When a call is blocked, Call Screener speaks the message contained in the ZapMessage.wav file to the caller. An example ZapMessage.wav file is included in the kit that comes in the download. Also, if you block anonymous calls, Call Screener plays an anonymous caller rejection message that instructs the caller how to remove their call blocking. Documentation is also included in the kit.
Version 4.0 adds the ability to gather from the internet the most complained about annoying callers and, optionally, to include them in your call blocking list. Version 4.0 also offers a vastly improved user interface.