ISDN or Integrated Services Digital Network represents:
– set of communication standards,
– these standards enables the digital transmission of video and audio, data, and other various network services simultaneous over the public switched telephone network,
– this transmission is through traditional circuits.
Features of ISDN
1. Integration of the data and speech and that too on the same line is the main feature of this protocol. This feature has led to the addition of several other features in this protocol that were not available previously in any other protocol and also in the CTS or classic telephone system.
2. ISDN provides several different types of access interfaces that are defined as follows:
- B – ISDN or broadband ISDN
- PRI or primary rate interface
- BRI or basic rate interface
3. This protocol operates on a circuit switched telephone network system. But then what makes it different? The difference is that through it the other packet switched networks can also be accessed.
4. It has been exclusively designed for transmitting the audio, video and data digitally over the normally used copper wiring in telephone systems.
5. It provides quite a better quality of voice than what could be provided by an analog phone.
6. It offers both i.e., for data it offers packet – switch connections at the rate of 64 kbps and for voice an data it provides circuit – switched connections.
7. The typical upstream and downstream transmission of data provided by the ISDN is 128 kbps which has opened for it the gates of internet access market.
8. ISDN is capable of achieving very high data rates through the application of channel bonding. The channels that are usually bonded are ISDN – B channels consisting of 4 BRIs.
9. ISDN cannot be specifically used with a protocol like Q.931. Here the part of the network is played by the ISDN and physical and the data – link layers are employed in the OSI model’s context.
10. ISDN mode is nothing but a suite of digital services when looked from the broad sense. These services exist on the first, second and third layers of the OSI model.
Use of ISDN
– The common use of the ISDN is limited to the protocols related to Q.931 and Q.931 itself.
– The application of these protocols is in the field of creating new circuit switched connections and breaking the already existing ones that are not in use.
– They are also used for providing calling features.
– ISDN plays a major role in video conference.
– It enables the simultaneous transmission of the text, audio and video between the individual users involved in the conference.
– With the integration feature, ISDN is capable of transmitting any number of simultaneous connections.
– These connections might be in any combination consisting of audio, video, data or fax over the same line.
– Also, a number of devices can be connected as required to the line.
– This simply means that the ISDN is capable of taking care of the communication needs of the people apart from TV and broadband internet access.
– It offers a much higher rate of transmission when compared to the other connections.
– ISDN does not require you buy many analog phone lines.
– ISDN also acts as a backup network for customers having leased the point to point lines like Eseva centers, LIC, SBI ATMs, and banks etc.