The technology that allows real-time communication in Voice over Internet Protocol (VoIP) services is primarily based on session initiation protocol (SIP) and other related protocols. These technologies enable voice data packets to be transmitted over the internet, allowing conversations to occur instantly without traditional telephone lines. VoIP services utilize digital transmission, which leads to improved call quality and reduced costs. Additionally, it integrates features like video conferencing, messaging, and collaboration tools, making it a versatile option for both businesses and individuals seeking efficient communication solutions.