RS-423, also known as TIA/EIA-423, is a technical standard originated by the

Electronic Industries Alliance The Electronic Industries Alliance (EIA; until 1997 Electronic Industries Association) was an American standards and trade organization composed as an alliance of trade associations for electronics manufacturers in the United States. They devel ...

that specifies electrical characteristics of a digital signaling circuit. Although it was originally intended as a successor to

RS-232C In telecommunications, RS-232 or Recommended Standard 232 is a standard originally introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a ''DTE'' (''data terminal equipment'') such ...

offering greater cable lengths, it is not widely used. RS-423 systems can transmit data on cables as long as . It is closely related to

RS-422 RS-422, also known as TIA/EIA-422, is a technical standard originated by the Electronic Industries Alliance that specifies electrical characteristics of a digital signaling circuit. It was meant to be the foundation of a suite of standards that ...

, which used the same signaling systems but on a different wiring arrangement. RS-423 differed primarily in that it had a single return pin instead of one for each data pin. RS-423 specifies an unbalanced ( single-ended) interface, similar to

RS-232 In telecommunications, RS-232 or Recommended Standard 232 is a standard originally introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a ''DTE'' (''data terminal equipment'') such ...

, with a single, unidirectional sending driver, and allowing for up to 10 receivers. It is normally implemented in integrated circuit technology and can also be employed for the interchange of serial binary signals between DTE & DCE.

Standard scope

RS-423 is the common short form title of American National Standards Institute (ANSI) standard ''ANSI/TIA/EIA-423-B Electrical Characteristics of Unbalanced Voltage Digital Interface Circuits'' and its international equivalent ''ITU-T Recommendation T-REC-V.10'', also known as ''X.26''. These technical

standard Standard may refer to: Symbols * Colours, standards and guidons, kinds of military signs * Standard (emblem), a type of a large symbol or emblem used for identification Norms, conventions or requirements * Standard (metrology), an object th ...

s specify the electrical characteristics of the unbalanced voltage digital interface circuit.''TIA/EIA STANDARD, Electrical Characteristics of Unbalanced Voltage Digital Interface Circuits, TIA/EIA-423-B'', May 1993 RS-423 provides for data transmission, using unbalanced or single-ended signals, with unidirectional/non-reversible, terminated or non-terminated transmission lines, point to point, or multi-drop.

Characteristics

RS-423 is closely related to the

standard, both of which use the same overall signaling system, but differ in that 422 has a dedicated return line for every data pin, while 423 uses a single return line. Use of a common ground is one weakness of RS-423 (and

): if devices are far enough apart or on separate power systems, the ground will degrade between them and communications will fail, resulting in a condition that is difficult to trace.National Semiconductor Application Note AN-1031 "TIA/EIA-422-B Overview", January 2000, National Semiconductor Inc.
page 2 - evaluate the combination of cable length and data rate. RS-423 specifies the electrical characteristics of a single unbalanced signal. The standard was written to be referenced by other standards that specify the complete DTE/DCE interface for applications which require a unbalanced voltage circuit to transmit data. These other standards would define protocols, connectors, pin assignments and functions. Standards such as

EIA-530 Currently known as TIA-530-A, but often called EIA-530, or RS-530, is a balanced serial interface standard that generally uses a 25-pin connector, originally created by the Telecommunications Industry Association. Finalized in 1987 (revision A f ...

(

DB-25 The D-subminiature or D-sub is a common type of electrical connector. They are named for their characteristic D-shaped metal shield. When they were introduced, D-subs were among the smallest connectors used on computer systems. Description, no ...

connector) and

EIA-449 The RS-449 specification, also known as EIA-449 or TIA-449, defines the functional and mechanical characteristics of the interface between data terminal equipment, typically a computer, and data communications equipment, typically a modem or term ...

( DC-37 connector) use RS-423 electrical signals.

Applications

The

BBC Micro The British Broadcasting Corporation Microcomputer System, or BBC Micro, is a series of microcomputers and associated peripherals designed and built by Acorn Computers in the 1980s for the BBC Computer Literacy Project. Designed with an emphas ...

computer uses RS-423 with a 5-pin

DIN connector The DIN connector is an electrical connector that was standardized by the ' (DIN), the German Institute for Standards, in the early 1970s. The male DIN connectors (plugs) feature a 13.2 mm diameter metal shield with a notch that limits the ...

. DEC used it extensively with a

Modified Modular Jack The Modified Modular Jack (MMJ) is a small form-factor serial port connector developed by Digital Equipment Corporation (DEC). It uses a modified version of the 6P6C modular connector with the latch displaced off-center so standard modular conne ...

connector. This was sometimes called "DEC-423".

Standard scope

Characteristics

Applications

See also

References

Further reading