EIA-232

EIA-232

(communications, standard)
(Formerly "RS-232") The most common asynchronous serial line standard. EIA-232 is the EIA equivalent of ITU-T V.24, and V.28.

EIA-232 specifies the gender and pin use of connectors, but not their physical type. RS-423 specifies the electrical signals. 25-way D-type connectors are common but often only three wires are connected - one ground (pin 7) and one for data in each direction. The other pins are primarily related to hardware handshaking between sender and receiver and to carrier detection on modems, inoperative circuits, busy conditions etc.

The standard classifies equipment as either Data Communications Equipment (DCE) or Data Terminal Equipment (DTE). DTE receives data on pin 3 and transmits on pin 2 (TD). A DCE EIA-232 interface has a female connector. DCE receives data from DTE on pin 2 (TD) and sends that data out the analog line. Data received from the analog line is sent by the DCE on pin 3(RD).

Originally DCE was a modem and DTE was a computer or terminal. The terminal or computer was connected (via EIA-232) to two modems, which were connected via a telephone line.

The above arrangement allows a computer or terminal to be connected to a modem with a straight-through (2-2, 3-3) cable. It is common, however, to find equipment with the wrong sex connector or with pins two and three reversed, requiring the insertion of a cable or adaptor wired as a gender mender or null modem. Such an adaptor is also required when connecting a computer directly to a terminal or to another computer without the use of modems.
References in periodicals archive ?
The products which Digi will supply to IBM include a PCI 128-port controller; an enhanced 16-port EIA-232 Remote Async Node; an RS-422 Remote Async Node; and a PCI EIA-232/RS-422 8 port async card.
2 kbps output streams from up to eight EIA-232 or V.
A rear serial communications port is available as either an EIA-232 or an EIA-485 interface.
Each LCE-16 module provides for up to 16 software-selectable asynchronous and/or synchronous circuits operating between 75 bps and 64 kbps over EIA-232, X.
Included are two built-in EIA-232 ports and an expansion port which can be configured at EIA 232, EIA 422/485, radio modem, leased-line modem, or dial-up modem using a plug-in communications card.
It offers wired EIA-232, EIA-485 and Ethernet connectivity as well as wireless Zigbee connectivity to remote sensors and thermostats.
Numerous interfaces are available, including EIA-232, EIA-422, EIA-485, J1708, Ethernet and Power-over-Ethernet.
New Octet[TM] 1x8 UTP/CatX transmitter with display-addressable EIA-232 provides adaptability, control and optimum video resolution over distance
The OfficeTime(TM) 21e is further fortified with a broad range of communications and management options, including Ethernet, up to 2 EIA-232 ports, NTP, interactive ASCII mode and TL1.
The SSU-2000e is further fortified with a broad range of communications and management interface modules, including 1 Ethernet port, 3 EIA-232 ports, interactive ASCII mode, TL1, NTP, SNMP, and an external Q3/CMIP adapter.
With the UltraPort SI, Perle is the first vendor to incorporate EIA-232, EIA-422 and EIA-485 interfaces on a single PCI serial card and provide the ability to individually configure each interface type using software commands.
It consists of an intelligent host adapter card plus a C/CON concentrator offering eight or 16 surge-protected EIA-232 ports.