Which solution is more economical than using regular long distance service and enables companies to route telephone calls over their data network?

Packet telephony is recognized as a more economical solution compared to traditional long-distance service, as it leverages the existing data network infrastructure to transmit voice calls. By encapsulating voice data into packets that can travel over IP networks, businesses can significantly reduce costs, particularly for long-distance communications. This efficiency arises from the ability to utilize already available data connectivity, which is often less expensive than traditional telephony routes.

Moreover, packet telephony allows for greater flexibility and scalability in managing communication needs. It can accommodate varying volumes of traffic and integrate with other data services seamlessly, making it a versatile choice for organizations.

VoIP, while also a cost-effective method for voice communication, generally refers to the technology itself rather than a protocol or service model. It encompasses a broader range of applications beyond just packet telephony. ISDN and PSTN, on the other hand, represent older technologies that do not offer the same level of economic flexibility as packet-based solutions and rely on dedicated circuit-switched connections, which can lead to higher costs and less efficient use of network resources.