What does ISDN stand for?

ISDN stands for Integrated Services Digital Network. This is a telecommunications standard that enables the digital transmission of voice, data, and video over traditional phone networks. Developed in the late 1980s, ISDN facilitates the simultaneous transmission of multiple types of data over a single digital line, enhancing the quality and efficiency of communications. It provides a framework for connecting different types of communication services and devices, allowing for faster and clearer connections compared to analog systems, which is a significant advantage in networking and telecommunications.

The other options do not accurately reflect the definition of ISDN. For example, "Industrial Standards Development Network" and "Internal System Data Network" do not pertain to the telecommunications context or the digital networking capabilities that ISDN offers. "Internet Services Digital Node" is also misleading, as it does not align with the actual purpose or function of ISDN in facilitating integrated digital communication.