Standards have been developed to provide diverse data communications systems with these common foundations for data transmission. Among these are interface standards (physical, electrical), hardware and software standards, and network standards, including codes, protocols and architectures.

It is important to know the names of standards and the organizations that develop them because these names are commonly used when discussing communications systems, and they are useful to those who want to be sure components follow particular standards to ensure compatibility.

Definitions

An interfaceis a shared boundary with common characteristics and meanings, or the point where devices connect.

A code is a set of rules specifying the representation of characters. A code set is formally known as an alphabet.

A protocol is a formal set of rules or agreements regarding message exchange.

An architecture is a collection of protocols and specifications for network communications (network blueprint).

A packet is one unit of a message that has been divided for transmission.

Organizations

The following organizations foster the development of communications
standards: (some common standards listed)

    ANSI:     ASCII character set

    CCITT:    V.xx modem specs, X.25 protocol

    EIA:      RS-232

    IEEE:     802 specifications, 802.3 (Ethernet), 802.5 (Token Ring)

    ISO:      OSI reference model 

ANSI
The American National Standards Institute (ANSI) is responsible for the establishment of many standards, including a number of data communications and terminal standards. ANSI is the recognized US representative body of CCITT , an international committee (described below). ANSI devised the ASCII character set, a widely used standard data transmission code.

CCITT
The International Consultative Committee for Telegraph and Telephone (CCITT) makes recommendations for international communication. CCITT lists what are referred to as V and X recommendations. V standards apply to telephone circuits and modems. X standards apply to public data networks (PDNs). CCITT recommendation X.25 has been adopted as a PDN standard. The X.25 communications protocol governs the way packets of data are transferred.

EIA
The Electronic Industries Association (EIA) is an organization of electronic manufacturers in the United States. EIA specifications are always preceded by RS (recommended standard). One of the most familiar standards is the RS-232 interface for serial data communication.

IEEE
The Institute of Electrical and Electronic Engineers (IEEE) sets standards for the electronics industry. The IEEE is divided into standards committees (or workgroups), each of which is responsible for one standards area. The 802 workgroups set standards for how devices on a network communicate with each other.

ISO
The International Standards Organization (ISO) developed the Open System Interconnection (OSI) network architecture model. The model defines the seven data-handling layers that are used in network architectures. A network architecture is an organizational plan for data communication.