The original DTEs were electromechanical teletypewriters, and the original DCEs were (usually) modems. RS-232 was first introduced in 1960 by the Electronic Industries Association (EIA) as a Recommended Standard.

The standard does not define bit rates for transmission, except that it says it is intended for bit rates lower than 20,000 bits per second. The character format and transmission bit rate are set by the serial port hardware, typically a UART, which may also contain circuits to convert the internal logic levels to RS-232 compatible signal levels. ASCII, EBCDIC, or others), the framing of characters (start or stop bits, etc.), transmission order of bits, or error detection protocols. The standard does not define such elements as the character encoding (i.e. Standard subsets of interface circuits for selected telecom applications.

Functions of each circuit in the interface connector.Interface mechanical characteristics, pluggable connectors and pin identification.Electrical signal characteristics such as logic levels, baud rate, timing, and slew rate of signals, voltage withstand level, short-circuit behavior, and maximum load capacitance.The Electronic Industries Association (EIA) standard RS-232-C as of 1969 defines: Thanks to their simplicity and past ubiquity, however, RS-232 interfaces are still used-particularly in industrial CNC machines, networking equipment and scientific instruments where a short-range, point-to-point, low-speed wired data connection is fully adequate. In modern personal computers, USB has displaced RS-232 from most of its peripheral interface roles. Personal computers used them for connections not only to modems, but also to printers, computer mice, data storage, uninterruptible power supplies, and other peripheral devices.Ĭompared with later interfaces such as RS-422, RS-485 and Ethernet, RS-232 has lower transmission speed, shorter maximum cable length, larger voltage swing, larger standard connectors, no multipoint capability and limited multidrop capability. The RS-232 standard had been commonly used in computer serial ports and is still widely used in industrial communication devices.Ī serial port complying with the RS-232 standard was once a standard feature of many types of computers.

The current version of the standard is TIA-232-F Interface Between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing Serial Binary Data Interchange, issued in 1997. The standard defines the electrical characteristics and timing of signals, the meaning of signals, and the physical size and pinout of connectors.

It formally defines signals connecting between a DTE ( data terminal equipment) such as a computer terminal, and a DCE ( data circuit-terminating equipment or data communication equipment), such as a modem. In telecommunications, RS-232 or Recommended Standard 232 is a standard originally introduced in 1960 for serial communication transmission of data. A DB-25 connector as described in the RS-232 standard Data circuit-terminating equipment (DCE) and data terminal equipment (DTE) network For RS-232 variants, including the common 9-pin connector, see serial port. This article is about the RS-232, standard.

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