A socket on a computer used to connect a modem, data acquisition terminal or other device via a serial interface (one data bit following the other). Serial ports provide very slow speeds and have been superseded by USB and other faster interfaces for peripheral connections to desktop computers. Although still widely used in data acquisition, the serial port is no longer found on new computers. Earlier PCs used the port for the mouse, and earlier Macintoshes used it to attach a printer.
DB (D-Sub) Connectors and COM Ports
If present, the serial port on the back of a PC is a male 9-pin connector (DE-9 D-sub connector). Earlier PCs may have had two 9-pin connectors or one 9-pin and one 25-pin (DB-25). On a PC, serial ports are called "COM ports," identified as COM1, COM2, etc. See COM1 and D-sub connectors.
Serial, Parallel and Game
In earlier PCs, one or two serial ports, one parallel port and one game port were included on the motherboard. On the first PCs, these ports were contained on a stand-alone expansion board plugged into the ISA bus. Contrast with parallel port. See serial interface and RS-232.
Faster, But Still Serial
The USB and FireWire (IEEE 1394) interfaces were added to PCs in 1998, offering a quantum jump in transfer rate, plus the ability to daisy chain large numbers of devices on the same bus. Like the legacy serial port, USB and FireWire are also serial interfaces. See USB and FireWire.
In Transition
As USB ports (left) began to proliferate, the serial and parallel ports (right) were included for a while, but eventually gave way entirely to USB.
DB (D-Sub) Connectors and COM Ports
If present, the serial port on the back of a PC is a male 9-pin connector (DE-9 D-sub connector). Earlier PCs may have had two 9-pin connectors or one 9-pin and one 25-pin (DB-25). On a PC, serial ports are called "COM ports," identified as COM1, COM2, etc. See COM1 and D-sub connectors.
Serial, Parallel and Game
In earlier PCs, one or two serial ports, one parallel port and one game port were included on the motherboard. On the first PCs, these ports were contained on a stand-alone expansion board plugged into the ISA bus. Contrast with parallel port. See serial interface and RS-232.
Faster, But Still Serial
The USB and FireWire (IEEE 1394) interfaces were added to PCs in 1998, offering a quantum jump in transfer rate, plus the ability to daisy chain large numbers of devices on the same bus. Like the legacy serial port, USB and FireWire are also serial interfaces. See USB and FireWire.
In Transition
As USB ports (left) began to proliferate, the serial and parallel ports (right) were included for a while, but eventually gave way entirely to USB.
 | Reproduced with permission from Computer Desktop Encyclopedia. Copyright (c) 1981-2009 The Computer Language Company Inc. All rights reserved. |
Additional Resources
- Advanced Serial Port Monitor 4.0.0 build 1124 (Windows)
- A power program that could be used to check the flow of data through computers' COM ports. Supports full duplex mode, flexible adjusting of parameters (baudrate, bits of data), output received data to file, automatic, manual mode, free data source, serial device emulation, plug-ins, and sniffer spy or monitor mode....
- Software downloads 2009-11-24
- MobileVT 4.0 (Mobile)
- Terminal emulator for Windows Mobile Pocket PC. Emulates telnet, vt102, vt100, vt52, ssh and ansi terminals; connects using network adapter, modem, serial port also bluetooth and Ir types; transfers files with xmodem, zmodem and scp protocols. Features a customizable colour display that can be scrolled using standard scrollbars or dragging...
- Software downloads 2009-11-23
- Serial Port Redirector 2.3.1 (Windows)
- Serial Port Redirector allows to create virtual serial ports assigned to IP addresses and TCP ports. Any serial communication software can use created virtual COM port, like usual hardware COM port, to send or receive serial data to and from assigned TCP/IP address and port. Serial Port Redirector allows to...
- Software downloads 2009-11-18
- Serial Port Control 2.1.5 (Windows)
- Serial Port Control is an inexpensive royalty-free component. You can use it with any development environment, such as VB, VB .Net, VC++, C#, Delphi, etc. Just put it on a form and vou've got all the functionality you need to access an RS232 port. The event driven architecture makes it...
- Software downloads 2009-11-18
- MacBrite 1.2.1 (Mac)
- MacBrite is a Mac OS X application for programming Classic BetaBrite LED signs. This version adds support of Intel based macs and Snow Leopard. Please note that BetaBrite prism sold by SAMS CLUB does not have a serial port.
- Software downloads 2009-11-17
- Virtual Serial Port Control 3.0.3 (Windows)
- If there is a task to provide interaction between communications application and your own program, there is no common solution to accomplish it. It is considered that communications applications are intended to work only with hardware serial devices connected to physical serial ports. Virtual Serial Port Activex is an ActiveX...
- Software downloads 2009-11-13
- Token2Shell 5.4 (Windows)
- Token2Shell supports all the widely used algorithms and methods for an SSH connection. Once Token2Shell is installed, simply type your server address and hit 'Enter'. Along with robust SSH features, Token2Shell also supports TELNET, TCP Direct, SerialCOM Port and ModemPhone connections. Token2Shell also includes a dedicated standalone application for SSH...
- Software downloads 2009-11-12
- SnapLogic snaps together different data flows and cuts integration costs
- I recently had a chance to catch up with one of my favorite Silicon Valley serial entrepreneurs Gauruv Dhillon. When I first met Mr Dhillon he was CEO of Informatica, one of the top software companies in Silicon Valley. These days he is founder,...
- Blog posts 2009-11-09
- Spark Loader 1.0 (Windows)
- Spark Loader is a boot loader for AVR microcontrollers, it is used for programming flash and EEPROM using a serial link between your computer and the microcontroller through any free COM port. Spark Loader consists of two parts: 1. On - chip boot loader: A hex file that resides at...
- Software downloads 2009-11-09
- goSerial 0.3 (Mac)
- Even though most peripherals today connect via USB or even through the air, there are still occasions when you need a simple serial cable. goSerial is built to provide you with an application that makes using your serial connection as easy as possible - just like you would expect from...
- Software downloads 2009-11-08
- DNC Precision Pro 2.6 build 58 (Windows)
- You can probably name several all-inclusive DNC tools but it is really a problem to find good DNC/CNC management software. DNC Precision is a feature-packed NC operation and management software, allowing full control of the process via serial port, which operates as a multiple NC management gateway allowing for secure...
- Software downloads 2009-11-06
- Ultra Serial Port Monitor 3.0.2 (Windows)
- Ultra Serial Port Monitor is a professional and powerful system utility for RS232/422/485 COM ports monitoring. The program monitors, displays, analyzes all serial port activity in a system. It is a very valuable tool for all software and hardware developers working with serial ports. Its powerful features and operation of...
- Software downloads 2009-11-03
- Express Scribe 5.00 (Windows)
- Express Scribe is a free transcription player featuring variable speed playback, foot pedal operation, speech recognition, file management and more. Ideal for playing dictation. Features: Variable speed playback constant pitch; Supports many professional foot pedals which connect to the game, serial or USB port to control playback; Uses 'hot' keys...
- Software downloads 2009-10-31
- Terminal CE 1.0 (Windows)
- Terminal CE is communication terminal dedicated for Windows CE system with .NET Compact Framework. Terminal allows to create connection and send/receive data using serial com port. Connection options: port name, baud rate, data bits, parity encoding and stop bit.
- Software downloads 2009-10-17
- Snow Leopard bug deletes all user data (Updated)
- Proves Apple is not perfectI know many ABMers that bashed Microsoft when a bug that only affected a very small user base came on in Windows 7 Release Candidate and said that Microsoft should pay and how can they release software with bugs. All software has bugs I don't...
- Discussion threads 2009-10-13
- Comm Operator 4.3 (Windows)
- Comm Operator is a powerful tool for serial port, TCP/IP and UDP port communication. It is professional software for debugging, testing and troubleshooting RS232 related devices. Data can be sent and received in Text/String, Hex and Decimal format. Auto send mechanics makes it a full functional device simulator. Send data...
- Software downloads 2009-10-12
- TConnector ActiveX 2.3.1.29 (Windows)
- The data acquisition software component TConnector extends your application (Microsoft Office applications, web-applications, Visual basic, C/C++, Delphi and .NET programs) with automated data collection features. The data acquisition ActiveX control TConnector reduces programming efforts to a minimum. It provides a very flexible solution for all kind of data acquisition applications....
- Software downloads 2009-10-09
- Express Dial 2.0 (Windows)
- Express Dial is a phone dialer for Windows computers and is designed to automate the dialing of a list of numbers as a predictive dialer or to call single numbers when required. Express Dial will use VoIP or any voice modem connected to the PC's serial port (so long as...
- Software downloads 2009-10-09
- AbsoluteTelnet Telnet / SSH / SFTP Client 8.14 (Windows)
- AbsoluteTelnet provides Telnet, SSH, SSH2, SFTP, dialup, and serial connectivity in the new tabbed multi-session interface or the classic single-session interface. A wide range of emulations are provided, including VT100, VT220, VT320, XTERM, WYSE60, ANSI, SCO-ANSI, ANSI-BBS, and QNX. Packed with options such as SOCKS5, IPV6, BIDI bidirectional text, Arabic...
- Software downloads 2009-10-08
- Advanced Serial Data Logger 3.7.1 build 1007 (Windows)
- Developing software that communicates with a device via COM port may be a challenging task without proper tools. Advanced Serial Data Logger is the unique serial port data logging and communication spying solution that supports various interfaces and features convenient user interface as well as flexibly configured modes of operation....
- Software downloads 2009-10-07
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