VoIP
VoIP (voice over Internet Protocol) is the technology that carries phone calls as data packets over an IP network such as the internet instead of over dedicated circuit-switched phone lines.
Also called: voice over IP, internet telephony, IP telephony
Speech is digitized, compressed and sent as a stream of packets; at the far end it is reassembled into audio. Because the call is data, it can be handled by software, recorded, transcribed, routed by rules, or answered by a program, and it can go anywhere the network reaches.
Most business phone systems are now VoIP, whether hosted in the cloud or run on-site, and they connect to ordinary phone numbers through SIP trunks and PSTN gateways. Call quality depends on the network: latency, jitter and packet loss show up as delay, robotic audio or dropped words.