What is ISDN?

ISDN is an abbreviation used for Integrated Services Digital Network. ISDN is a digital communication technology. In this technology, speech and data are transferred with the help of existing phone lines. ISDN technology offers faster data transfer rates and higher quality of calls.

The ISDN technology is digital in nature. It is mainly used by big organizations or companies where there is a need for faster data transfer rates, and improved quality of calls. The ISDN technology can provide many simultaneous line connections at a time. It can handle 10-30 line connections at a time.

Operation of ISDN

The operation of ISDN consists of the following stages:-

• At first, the operation of ISDN is done with the help of the digital domain. It makes use of digital signals to perform the task of transmitting data, voice and other multimedia content.
• The ISDN operate using two types of interfaces. The first interface which is used is BRI, which provides a channel bandwidth of 128 Kbps. It consists of two bearer channels and one delta channel. The other interface which is used is PRI, which provides a channel bandwidth of 64 Kbps. It consists of multiple Bearer channels and one Delta Channel.
• When the user initiates a call, the ISDN establishes a digital connection between the calling parties and the called parties. The establishment of digital connection involves signaling to establish, maintain and terminate connections between the ISDN terminals.
• The Bearer channel which was used does the task of carrying of actual data of the user, like voice or other digital information.
• While the Delta channel is primarily used for signaling and control purposes.
• The ISDN utilizes circuit-switching and packet-switching modes for the transmission. Circuit-switched mode is used to allocate dedicated channels for the duration of the call. While packet-switched mode is the transmission of data in the form of packets.

In this article, we will cover communication protocols that are used for the transmission of data and voice. We will have a look at what is ISDN and PSTN. Then we will look at the differences between them. After this, we will look at the advantages, disadvantages and applications of both.