What is ISDN ?
ISDN (Integrated Services Digital Network) is a set of communication standards for digital transmission of voice, video, and data over traditional phone networks.
It was designed to replace analog telephone systems and provide faster and more reliable communication services. ISDN allows multiple types of services to be carried over a single line, such as voice calls, fax, data, and video conferencing.
Key features of ISDN:
- Digital Transmission: ISDN uses digital signals, providing higher quality and more reliable connections compared to analog systems.
- Multiple Channels: ISDN lines can carry multiple channels simultaneously, allowing for different services to be used at the same time (for example, voice and data).
- B channels (Bearer channels): Used for data transmission (e.g., voice, video, or file transfer).
- D channel: Used for signaling and control purposes.
- Faster Data Transmission: ISDN offers higher speeds than traditional dial-up connections, typically up to 128 kbps with two B channels (in the case of ISDN BRI).
- Wide Applications: It was commonly used for voice communication, video conferencing, internet access, and connecting remote offices before broadband internet became more widespread.
Types of ISDN:
- ISDN BRI (Basic Rate Interface): Primarily used for home and small business use, providing two 64 kbps B channels and one 16 kbps D channel.
- ISDN PRI (Primary Rate Interface): Used for larger organizations and offers 23 B channels and one 64 kbps D channel in North America (or 30 B channels and one D channel in Europe).
ISDN has become less common in modern communications, as broadband internet and VoIP (Voice over Internet Protocol) technologies have largely replaced it for many applications. However, it may still be used in specific industries or areas where high-speed internet options are limited.