RS-423

{{Infobox fieldbus protocol

|name = RS423

| standard = EIA RS-423

|governing_body =

|website =

|type_of_network =

|physical_media = Group of copper cables

|network_topology = Point-to-point, Multi-dropped

|maximum_devices = 10 (1 driver & 10 receivers)

|maximum_distance = 1200 meters (4000 feet)

|maximum_speed =

|device_addressing =

|mode_of_operation = Single-ended (unbalanced)

|maximum_baud_rate =Up to 100kbit/s

|voltage = -6V to +6V (maximum)

|mark1=-4V to -6V

|space0=+4V to +6V

|available_signals=Tx, Rx, GND

|connector_types = Not specified

}}

RS-423, also known as TIA/EIA-423, is a technical standard originated by the Electronic Industries Alliance that specifies electrical characteristics of a digital signaling circuit. Although it was originally intended as a successor to RS-232C offering greater cable lengths, it is not widely used.

RS-423 systems can transmit data on cables as long as {{Convert|1200|m|sp=us}}.{{dubious|Maximum length|date=September 2021}} It is closely related to RS-422, 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.{{cite web |title=EIA-423 |url=http://foldoc.org/rs-423|publisher=foldoc.org|access-date=2021-07-08}}

RS-423 specifies an unbalanced (single-ended) interface, similar to RS-232, with a single, unidirectional sending driver, and allowing for up to 10 receivers.Buchanan W.J. (2004) RS-422, RS-423 and RS-485. In: The Handbook of Data Communications and Networks. Springer, Boston, MA.{{ISBN|978-1-4757-1067-0}} page 627 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,{{cite web |title=V.10 : Electrical characteristics for unbalanced double-current interchange circuits operating at data signalling rates nominally up to 100 kbit/s |url=https://www.itu.int/rec/T-REC-V.10/en%20V.10%20ITU%20Recommendation%20T-REC-V.10|website=itu.int |access-date=3 May 2023}} also known as X.26. These technical standards 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

File:RS signal rate.svg

RS-423 is closely related to the RS-422 standard, both of which use the same overall signaling system, but differ in that RS-422 has a dedicated return line for every data pin, while RS-423 uses a single return line. Use of a common ground is one weakness of RS-423 (and RS-232): 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.[http://www.ti.com/lit/an/snla044b/snla044b.pdf 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.{{citation needed|date=May 2023}}

These other standards would define protocols, connectors, pin assignments and functions. Standards such as EIA-530 (DB-25 connector) and EIA-449 (DC-37 connector) use RS-423 electrical signals.{{citation needed|date=May 2023}}

Applications

The BBC Micro computer uses RS-423 with a 5-pin DIN connector. DEC used it extensively with a Modified Modular Jack connector. This was sometimes called "DEC-423".{{citation needed|date=May 2023}}

RS-423

Standard scope

Characteristics

Applications

See also

References

Further reading