Voice over IP - Wikipedia
https://en.wikipedia.org/wiki/Voice_over_IP
Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP)...
What Is IP Telephony? And Why Should Businesses Use It?
https://www.nextiva.com/blog/what-is-ip-telephony.html
How Does IP Telephony Work? IP telephone systems use the Internet Protocol (IP) or other digital protocols to transfer voice communications over the internet. If you use an IP PBX system, the data...