ISDNää

ISDNää is a term used in speculative literature and niche technical projects to denote a hypothetical extension of the Integrated Services Digital Network (ISDN). In this concept, ISDNää preserves the core architecture of ISDN, including B channels for user data and a D channel for signaling, while adding features aimed at real-time multimedia and higher security. It is not an ITU standard, and there is no official certification; existing real-world ISDN systems may be connected to ISDNää-enabled devices through backward-compatible interfaces.

Technical characteristics include adaptive channel management, where the system can allocate B channels dynamically based on real-time traffic, and an enhanced signaling layer that supports QoS negotiation for low-latency audio streams. ISDNää also envisions optional encryption for user data on B channels and integrity protections for signaling messages. The design emphasizes compatibility with legacy ISDN equipment, so calls can fall back to standard ISDN when ISDNää features are unavailable.

Status and usage: ISDNää remains theoretical or experimental. Some university research projects and hobbyist networks have built small testbeds to explore the ideas, but there is no broad deployment in public networks. The concept is sometimes discussed as a thought experiment about how legacy digital telephony could evolve to handle modern multimedia needs while preserving the ubiquity of ISDN infrastructure.