Which technology is known for eliminating the need for long-distance phone charges?

VoIP, or Voice over Internet Protocol, is the technology that allows users to make voice calls using the internet instead of traditional phone lines. By converting voice signals into digital packets and transmitting them over IP networks, VoIP eliminates the long-distance phone charges typically associated with PSTN systems, which rely on circuit-switched networks and charge per minute for long-distance calls.

This capability is particularly advantageous for both individuals and businesses, as it can lead to significant savings on communication costs, particularly for international calls. In addition to cost savings, VoIP services often come with added features such as voicemail-to-email, video calling, and conference calling, further enhancing their appeal over traditional telephony services.

Other technologies listed, such as PSTN, ISDN, and Frame Relay, are designed for different communication needs but do not provide the same cost-effective solution for long-distance communications as VoIP does.