Before the coming of age of ISDN, the analogy initial explosion of communication services, also known as Plain Old Telephone System (POTS) is the only source of the communication world. POTS is the earlier to the Post Office Telephone Service acronymic / System but the last time the post office stopped offering telephone service. Especially including the quality of the relevant paragraph POTS customer's home office move. This type of communication limitations. Long distance calls will be deployed through operators and switchboards that make them very long to destroy. There is also the issue of static lines of inference known as the annoying noise communications.
In 1960 years, the telecommunications sector began his work to change the analog system sends packets of digital data and digital switching. United Nations and the International Advisory Committee Telephone Telegraph (CCITT, French short), now known as the International Telecommunication Union Telecommunication (ITU-T) are encouraged to actively promote research for Integrated Services Digital Network (ISDN) to begin the process to recommend and provide digitalized international standards of communication services. It was formed in 1984.
Network, two major in the United States, North and Telecomm AT & T took the first step toward implementation of ISDN, but not operate tools and programs available to existing communications networks, this has led to the decline worldwide ISDN. In 1990, for businesses around the world, National ISDN 1 (NI-1) performed with the existing proprietary tools for communication services, this means that people do not need to change the brand or purchase software for the web. This set standards and procedures for digital communications technology that is then used by everyone.
ISDN has caused the sound quality is better and Internet access for a packet-switch connections. Including ISDN, voice and data published by the media channel (channel B) and bandwidth of 64 kb / s, sometimes 56 kb / s on the phone line, which carries 52 kb / s. A data channel (D channel) is used to control the network services and associations to build, broken relationships and bring the data bearer channels. This brings Bandwidth of 16 kb / s or 64 kb / s.
There are services provided to two ISDN. This is known as BRI and PRI. BRI - Basic Rate Interface consists of two 64 kb / s bearer channels and one 16 kb / s data channel, which reaches 144 kb / s, as the name suggests, usually BRI has enough bandwidth to individual users. PRI - Primary Rate Interface is used for clients that require large bandwidth. Size 23 is comprised of 64 kb / s B channels and one 64 kb / s D channel a total of 1.536 MB / s. Sometimes, service can be the PRI B channels 30 and one D channel for a total of 1.984 MB / s.
For now, the future lies with ISDN Broadband ISDN (BISDN). This involves the transfer of data, voice and video at the same phone line using an optical fiber can carry data rates of 155 Mb / s to 622 Mb / s and so on. This is a great topic for research and development.
