RS232 Serial Interfaces
Last Updated: April 1, 2025
Description
The RS-232 serial interface is a standard for serial communication transmission of data. It is primarily used to connect Data Terminal Equipment (DTE) such as computers to Data Communication Equipment (DCE) like modems. The RS-232 standard defines the electrical characteristics and timing of signals, as well as the physical size and pinout of connectors.
Working Principle
RS-232 operates as a single-ended, full-duplex interface, meaning it allows for simultaneous two-way communication between devices. It uses a point-to-point connection, where one driver connects to one receiver. The interface relies on a ground wire connection to provide a common reference for transmit and receive signals. RS-232 achieves noise immunity through high signal amplitudes, with logic levels defined by specific voltage ranges: a logic zero is represented by a voltage from +3V to +15V, and a logic one by a voltage from -3V to -15V. This standard is useful because it provides a reliable method for data exchange over short distances, making it ideal for connecting peripheral devices to computers.
Applications
RS-232 is widely used in computing and data storage for connecting peripherals such as keyboards, mice, and printers to computers. It is also employed in industrial automation and control systems, where it connects programmable logic controllers (PLCs) and other devices to central systems for data gathering and machinery control.
Advantages over other Serial Interfaces
RS-232 is the most prolific communication port due to its simplicity and reliability. It is particularly advantageous for point-to-point communication at speeds below 20,000 bits per second and distances up to 50 feet. Unlike RS-422 and RS-485, which use differential signals, RS-232's single-ended signaling is straightforward and cost-effective for short-distance communication.
Limitations
RS-232 is limited by its relatively low data transmission speed and short maximum cable length. It is rated for speeds below 20,000 bits per second and distances up to 50 feet, although these limits can sometimes be exceeded with shielded low-capacitance cables. The standard's susceptibility to electrical noise and cable capacitance further restricts its performance over longer distances.
Considerations
When considering RS-232 for a project, initial costs are generally low due to its widespread availability and simplicity. Operating expenses are minimal, but the interface's durability and accuracy can be affected by environmental factors such as electrical noise. Replacement and maintenance costs are typically low, but users should be aware of the limitations in speed and distance, which may necessitate additional equipment or alternative interfaces for more demanding applications.
from Advantech
Isolated RS-232, 2-Ports, DB9, PCIe I/F. Meets Advantech Standard iDoor Technology. PCI Express ® Mini Card Specification Revision 1.2 compliant. Speeds up to 921.6 kbps for extremely fast data transmission. Supports any baud rate setting (50bps~921.6kbps). Supports both Isolated &... [See More]
- Serial Protocol: RS232
- Data Rate: 0.0500 to 922
- Network / Bus: PCI; PCI Express Mini Card Revision 1.2
- Connector: DB9; 2 x Male DB9
from Yaskawa America, Inc. - Motion Division
Features. Easy Web Insterface. Every VIPA SLIO E/IP and Modbus TCP Fieldbus module has a web interface for displaying diagnostic information and status of attached modules. A simple connection of your network allows remote access to your VIPA SLIO modules. High Speed Backpland Bus. Achieve reaction... [See More]
- Serial Protocol: RS232
- Connector: Terminal Module
- Data Rate: 0.1500 to 115
- Features: Indicators
from Advantech
Non-Isolated RS-232, DB37 to 4-port DB9, PCIe I/F. Meets Advantech Standard iDoor Technology. PCI Express ® Mini Card Specification Revision 1.2 compliant. Speeds up to 921.6 kbps for extremely fast data transmission. Supports any baud rate setting (50bps~921.6kbps). Supports both Isolated... [See More]
- Serial Protocol: RS232
- Data Rate: 0.0500 to 922
- Network / Bus: PCI; PCI Express Mini Card Revision 1.2
- Connector: 1 x Female DB37
from Moxa Inc.
The ICF-1150 series support 2 serial ports, with a D-sub connector for RS-232 communication and a removable terminal block for RS-422 or RS-485 communication. The 3 ports (2 serial ports and one fiber port) are completely independent. When an ICF-1150 converter receives data from any one port, it... [See More]
- Serial Protocol: RS232; RS422; RS485; RS232/422/485
- Form Factor: DIN Rail
- Connector: SC or ST
- Features: ESD Protection
from Radicom Research, Inc.
Radicom LSDB8900 industrial WiFi/LAN to Serial/USB/BLE product line is an all new wireless to wire gateway solution. With built-in powerful CPU to process all necessary functions and features, the LSDB8900 series product line is a perfect solution for remote data communication through WiFi/Ethernet... [See More]
- Serial Protocol: RS232; RS422; RS485; RS232/422/485
- Data Rate: 922
- Network / Bus: 10/100Base-T; USB (optional feature)
- Connector: Wireless
from Patton Electronics Co.
The Model 2017RC is an async device that operates bi-directionally in full- or half-duplex modes.The Model 2017RC occupies one slot of the 1000R/16 front-load rack. It has dual independent converters that enable two async DTE RS-232 devices to communicate with two 20-mA current loop devices over two... [See More]
- Serial Protocol: RS232
- Connector: RJ-11; RJ-45
- Data Rate: 115
- Form Factor: PCB
from Ultra Energy
When you have multiple signals to transmit over fiber optic cable, we offer two solutions; one for bi-directional, point-to-point applications, and one for multi-node applications, with built-in self-healing ring functionality. Multi-Node MX Multiplexer. The EOTec 2000 Multi-Node MX Multiplexer can... [See More]
- Serial Protocol: RS232; RS485
- Form Factor: DIN Rail
- Number of Ports: 2
from Sealevel Systems, Inc.
This product is classified as legacy and is not recommended for new or high volume designs. Sealevel will support legacy products through technical and warranty support, software drivers and product manuals. Please contact Sales for further information. For new product designs, we recommend the... [See More]
- Serial Protocol: RS232
- Number of Ports: 8
- Network / Bus: CompactPCI
- Connector: DB25
from ProSoft Technology, Inc.
The MVI56-GSC module is a single slot, backplane compatible solution for the Rockwell Automation ControlLogix platform. This module has two powerful and fully configurable ASCII communication ports, each supporting the sending and receiving of large ASCII character strings. With the implementation... [See More]
- Serial Protocol: RS232; RS422; RS485; RS232/422/485
- Data Rate: 115
- Network / Bus: ControlLogix
- Number of Ports: 3
from Electro Standards Laboratories
FEATURES: Easily inserted in series between DTE (Data Terminal Equipment) and DCE (Data Com Equipment). 50 Test points to access all 25 pins of both DCE and DTE connector. Test synchronous or asynchronous modems, terminals and multiplexers. 24 mini-switches provide capability to program each signal... [See More]
- Serial Protocol: RS232
- Operating Humidity: 10 to 90
- Operating Temperature: 0.0 to 50
from Connect Tech Inc.
Frees devices from a physical PC connection [See More]
- Serial Protocol: RS232
- Data Rate: 461
- Network / Bus: BACnet; DNP3; 10Base-T; Modbus; 100Base-TX
- Number of Ports: 2
from RFID, Inc.
There are a multitude of Interfaces, some of which incorporate their own Reader in a single pcb or housing. Each incorporate just about every protocol specification available including protocols of RS232, RS422, RS485, hex or bcd parallel outputs, all baud rates to 9600, modes of operation ranging... [See More]
- Serial Protocol: RS232
- Form Factor: Rack Mounted
- Connector: Screw Terminals, 9-Pin Connector
- Operating Temperature: -40 to 55
from Patlite (USA) Corporation
The PHC-100A is a serial interface converter to control most PATLITE products (audio and visual) by relays via a SERIAL RS-232C connection. Connect the unit to the RS-232C port on a programmed personal computer with an RS-232 controller program. [See More]
- Serial Protocol: RS232
from Opto 22
Addressable RS232 Interface 120 VAC [See More]
- Serial Protocol: RS232
- Data Rate: 38.4
- Network / Bus: Multidrop Network
- Form Factor: Stand Alone
from American Portwell Technology Inc.
Self powered DB9 RS-232 to DB9 RS-422 Serial Data Converter [See More]
- Serial Protocol: RS232; RS422
- Connector: DB9
- Network / Bus: USB
- Form Factor: Portable
from TOP-electronics USA
W &T 38211, Interface USB/RS232/RS422/RS485 Industry 1kV isolation with overvoltage protection. Product properties: Bi-directional conversion of USB into RS232, RS422 or RS485 interface USB 2.0 Full Speed Device (12 Mbit/s). Power supply via USB Compatible with RS485 2-wire and 4-wire bus... [See More]
- Serial Protocol: RS232; RS422; RS485
- Network / Bus: USB
from Moxa Inc.
The TCF-142 media converter is equipped with a multiple interface circuit that can handle RS-232 or RS-422/485 serial interfaces and multi-mode or single-mode fiber. TCF-142 converters are used to extend serial transmission up to 5 km (TCF-142-M with multi-mode fiber) or up to 40 km (TCF-142-S with... [See More]
- Serial Protocol: RS232; RS485; RS232/422/485
- Form Factor: Wall Mount
- Connector: SC or ST
- Features: ESD Protection
from Sealevel Systems, Inc.
The 3088 ISA serial interface provides PC systems with two RS-232 Asynchronous links to data collection and other devices. Modems, data entry terminals and plotters are some devices that use RS-232 protocols. The 3088 allows for individually selectable interrupts (2-5, 7, 10-12 and 15). This product... [See More]
- Serial Protocol: RS232
- Number of Ports: 2
- Data Rate: 115
- Connector: DB9
from ProSoft Technology, Inc.
The inRAx Modbus Master/Slave Communications module is designed to allow ControlLogix processors to interface easily with Modbus protocol-compatible devices and hosts. The MVI56-MCM module acts as an input/output module between the Modbus network and the Rockwell Automation backplane. The data... [See More]
- Serial Protocol: RS232; RS422; RS485; RS232/422/485
- Number of Ports: 2
- Network / Bus: Modbus
- Connector: RJ-45
from RFID, Inc.
There are a multitude of Interfaces, some of which incorporate their own Reader in a single pcb or housing. Each incorporate just about every protocol specification available including protocols of RS232, RS422, RS485, hex or bcd parallel outputs, all baud rates to 9600, modes of operation ranging... [See More]
- Serial Protocol: RS232; RS422
- Features: Indicators
- Connector: DB25; 6-Pin Circular DIN, 5-Pin Circular DIN
- Operating Temperature: -40 to 55
from Opto 22
Addressable RS232 Interface DC [See More]
- Serial Protocol: RS232
- Data Rate: 38.4
- Network / Bus: Multidrop Network
- Form Factor: Stand Alone
from American Portwell Technology Inc.
Self powered DB9 RS-232 to DB9 RS-485 Serial Data Converter [See More]
- Serial Protocol: RS232; RS485
- Connector: DB9
- Network / Bus: USB
- Form Factor: Portable
from TOP-electronics USA
W &T 81009, Fiber Optic Interface to RS232, 9 pin/PC. The 81009 Interface transmits serial RS232 data via plastic duplex fibers over a distance of up to 80 meters. The 81009 Interface powers itself from the signal lines of the serial interface and requires no additional external power supply... [See More]
- Serial Protocol: RS232
from Moxa Inc.
The TCF-90 is a compact media converter that transmits RS-232 signals over optical fiber. Power is derived from either the serial port or an external power source. The TCF-90 extends RS-232 transmission up to 5 km with multi-mode fiber, or up to 40 km with single-mode fiber. A pair of TCF-90... [See More]
- Serial Protocol: RS232
- Number of Ports: 1
- Data Rate: 115
- Connector: DB9
from Sealevel Systems, Inc.
THIS PRODUCT IS OBSOLETE DUE TO LACK OF COMPONENT AVAILABILITY. PLEASE CONTACT YOUR SALES REPRESENTATIVE FOR FURTHER INFORMATION AND NEW PRODUCT ALTERNATIVES. Sealevel will support legacy products through technical and warranty support, software drivers and product manuals. Please contact Sales for... [See More]
- Serial Protocol: RS232
- Number of Ports: 4
- Data Rate: 461
- Connector: DB25
from RFID, Inc.
There are a multitude of Interfaces, some of which incorporate their own Reader in a single pcb or housing. Each incorporate just about every protocol specification available including protocols of RS232, RS422, RS485, hex or bcd parallel outputs, all baud rates to 9600, modes of operation ranging... [See More]
- Serial Protocol: RS232; RS422
- Operating Temperature: -40 to 55
- Connector: DB25; DIN 41612 Type C
from Opto 22
The SNAP-SCM-232 provides two RS-232 serial communication ports for two channels of high-speed, isolated serial data. Used with a SNAP PAC brain or R-series controller, the module connects serial devices such as printers, scales, chart recorders, and barcode systems to an Ethernet network for... [See More]
- Serial Protocol: RS232
- Data Rate: 115
- Network / Bus: SNAP Brains
- Number of Ports: 2
from American Portwell Technology Inc.
USB to single DB9 RS-232 with included cable [See More]
- Serial Protocol: RS232
- Number of Ports: 1
- Network / Bus: USB
- Connector: DB9
from TOP-electronics USA
W &T 81025, Fiber Optic Interface,RS232,25 pin/PC, Female [See More]
- Serial Protocol: RS232
from Sealevel Systems, Inc.
THIS PRODUCT IS OBSOLETE DUE TO LACK OF COMPONENT AVAILABILITY. PLEASE CONTACT YOUR SALES REPRESENTATIVE FOR FURTHER INFORMATION AND NEW PRODUCT ALTERNATIVES. Sealevel will support legacy products through technical and warranty support, software drivers and product manuals. Please contact Sales for... [See More]
- Serial Protocol: RS232
- Number of Ports: 8
- Data Rate: 461
- Connector: DB25
from TOP-electronics USA
W &T 81029, Fiber Optic Interface, RS232, 9 pin/PC. Low power version for distances <20 meters. The 81029 interface transmits serial RS232 data via plastic duplex fiber over a distance of up to 20 meters. The converter is powered by the serial interface and therefore does not require an... [See More]
- Serial Protocol: RS232