Scenery of infotelematic communications in the '70s

In the '70s the devices and network equipments were built mostly by companies that made hardware and software with the aim of using them in an exclusive ecosystem of their own products, without too much concern for the possibility of communication with other manufacturers' systems. In such a scenario it was therefore very easy that when connecting two computers using different encodings in terms of character representation, ASCII and UNICODE for example, the two systems were not able to communicate with each other to complete the connection. In all respects, at that time only real Closed Systems existed (Closed Systems).

Over time, however, it began to understand the undeniable advantage that came guaranteed by sharing knowledge through data; this led to the need for having to connect communication devices at ever greater distances, like two locations located in different cities. It so happened that communications experts found themselves inevitably, more and more often having to connect IT systems to other computers through devices and devices of the most disparate, built by different manufacturers and often, therefore, unable to communicate with each other.

In this way, the International Organization for Standardization (ISO) decided to lay the foundations for coordinating the development of a standard for logical network architecture and the interconnection of processing systems. This study led in 1984 to the drafting of the set of specifications of the OSI (Open System Interconnection) model, that is a series of communication protocols able to make the communication of systems with hardware, languages and heterogeneous features feasible, effectively opening the road to the first Open Systems (Open Systems).

The document that illustrates these activities is known as the "Basic Reference Model" or ISO 7498, and still represents the standard open format reference model.

ISO/OSI model

Technologies and switching protocols

Technologies and routing IP protocols

WAN (Wide Area Networks)

IP addresses management

Applicative level protocols

Networks security elements

Video/voice/data convergence