Write Caller ID Software for VoIP Phone system

HI, I neet software written to capture the caller ID phone number from a VoIP phone system, I will also need some kind of external box or does can I plug the VoIP phone line into my ethernet to usb port adapter and use that? When a call comes in the software will need to read the caller ID number from the VoIP phone system and send the phone number to an API for my website (I will prove the API). The programmer must have a VoIP phone system or access to one to test.