Integrated Services Digital Network (ISDN) refers to a telecommunications protocol and set of standards that facilitate the transmission of voice, video, and data simultaneously over traditional copper wires. It enables the integration of various communication services into one network, thereby allowing users to transmit multiple types of information using a single connection.
ISDN provides a range of services, including voice communication, data transfer, facsimile transmission, video conferencing, and internet access. It achieves this by dividing the available bandwidth into multiple channels, where each channel can be used for different types of information. These channels are known as "bearer channels" for data transmission and "control channels" for signaling and call setup.
ISDN uses digital signaling technology, which ensures high-quality communication and eliminates the limitations of analog systems. It offers two primary interface standards: Basic Rate Interface (BRI) and Primary Rate Interface (PRI). BRI consists of two bearer (B) channels and one data (D) channel, allowing a user to establish two simultaneous voice calls and transfer data at a rate of 128 kilobits per second. PRI, on the other hand, provides a higher capacity with multiple B and D channels, enabling multiple voice calls and higher data transfer rates.
ISDN played a significant role in the transition from traditional analog telephone networks to digital communication. However, with the emergence of more advanced technologies like broadband and internet-based telephony, ISDN has gradually been replaced in many regions.
