Eia rs232 standard pdf

This article is about the RS-232 standard. RS-232 from most eia rs232 standard pdf its peripheral interface roles. USB-to-RS-232 converter or a

This article is about the RS-232 standard. RS-232 from most eia rs232 standard pdf its peripheral interface roles.

USB-to-RS-232 converter or an internal expansion card with one or more serial ports to connect to RS-232 peripherals. Nevertheless, thanks to their simplicity and past ubiquity, RS-232 interfaces are still used—particularly in industrial machines, networking equipment, and scientific instruments where a short-range, point-to-point, low-speed wired data connection is adequate. Interface mechanical characteristics, pluggable connectors and pin identification. Functions of each circuit in the interface connector. Standard subsets of interface circuits for selected telecom applications. The C revision of the standard was issued in 1969 in part to accommodate the electrical characteristics of these devices.

RS-232 compatible interface on their equipment often interpreted the standard idiosyncratically. The resulting common problems were non-standard pin assignment of circuits on connectors, and incorrect or missing control signals. A common deviation from the standard was to drive the signals at a reduced voltage. 5 V and labeled them as “RS-232 compatible”.

It remained in widespread use into the late 1990s. In personal computer peripherals, it has largely been supplanted by other interface standards, such as USB. The standard has been renamed several times during its history as the sponsoring organization changed its name, and has been variously known as EIA RS-232, EIA 232, and, most recently as TIA 232. Revision C was issued in a document dated August 1969.

Revision D was issued in 1986. 24, but equipment built to the current standard will interoperate with older versions. 25 volts, and the circuit capacitance limit was expressly stated as 2500 pF. Revision E of EIA-232 introduced a new, smaller, standard D-shell 26-pin “Alt A” connector, and made other changes to improve compatibility with CCITT standards V. Because RS-232 is used beyond the original purpose of interconnecting a terminal with a modem, successor standards have been developed to address the limitations. The large voltage swings and requirement for positive and negative supplies increases power consumption of the interface and complicates power supply design.

The voltage swing requirement also limits the upper speed of a compatible interface. Single-ended signaling referred to a common signal ground limits the noise immunity and transmission distance. Multi-drop connection among more than two devices is not defined. While multi-drop “work-arounds” have been devised, they have limitations in speed and compatibility. The standard does not address the possibility of connecting a DTE directly to a DTE, or a DCE to a DCE.

The definitions of the two ends of the link are asymmetric. DTE-like or DCE-like interface and which connector pin assignments to use. No method is specified for sending power to a device. The 25-pin D-sub connector recommended in the standard is large compared to current practice. RS-232 compatible serial port of the original IBM PC design. Advantages compared to RS-232 are that USB is faster, uses lower voltages, and has connectors that are simpler to connect and use.