RS-232

In <a href="/facts/Telecommunications/vxoj1cxR">telecommunications</a>, RS-232 or <a href="/facts/Recommended_Standard/CIxRjt05">Recommended Standard</a> 232 is a <a href="/facts/Technical_standard/P4orT1SM">standard</a> introduced in 1960 for <a href="/facts/Serial_communication/r5xP7P1c">serial communication</a> transmission of data. It formally defines signals connecting between a DTE (<a href="/facts/Data_terminal_equipment/o7qvJVQq">data terminal equipment</a>) such as a <a href="/facts/Computer_terminal/fSlx05qV">computer terminal</a> or <a href="/facts/Personal_computer/koaYfNce">PC</a>, and a DCE (<a href="/facts/Data_circuit-terminating_equipment/asE4FHvh">data circuit-terminating equipment</a> or <a href="/facts/Data_communication_equipment/asE4FHvh">data communication equipment</a>), such as a <a href="/facts/Modem/9H0Xwtq0">modem</a>. The standard defines the electrical characteristics and timing of signals, the meaning of signals, and the physical size and <a href="/facts/Pinout/AtksXTwD">pinout</a> of connectors. 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 RS-232 standard had been commonly used with <a href="/facts/Serial_port/VpcrH530">serial ports</a> and <a href="/facts/Serial_cable/SSI6eMoY">serial cables</a>. It is still widely used in industrial communication devices.
A serial port complying with the RS-232 standard was once a standard feature of many types of computers. <a href="/facts/Personal_computer/koaYfNce">Personal computers</a> used them for connections not only to modems, but also to <a href="/facts/Printer_(computing)/PnDF2QuF">printers</a>, <a href="/facts/Computer_mice/fJpa1tUE">computer mice</a>, data storage, <a href="/facts/Uninterruptible_power_supplies/aYD6Yo6L">uninterruptible power supplies</a>, and other peripheral devices.
Compared with later interfaces such as <a href="/facts/RS-422/le2rYC8T">RS-422</a>, <a href="/facts/RS-485/YEABejzm">RS-485</a> and <a href="/facts/Ethernet/nMfhU8tU">Ethernet</a>, RS-232 has lower transmission speed, shorter maximum cable length, larger voltage swing, larger standard connectors, no multipoint capability and limited multidrop capability. In modern personal computers, <a href="/facts/USB/XcIKWLyg">USB</a> has displaced RS-232 from most of its peripheral interface roles. 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.

RS-232 open-in-new

RS-232