Webopedia on Google+Webopedia on TwitterWebopedia on FacebookTech Bytes Blog
Main » TERM » C »

COM

(1) In DOS systems, the name of a serial communications port. DOS supports four serial ports: COM1, COM2, COM3, and COM4. However, most software uses system interrupts to access the serial ports, and there are only two IRQ lines reserved. This means that the four COM ports share the same two IRQ lines. Typically, COM1 and COM3 use IRQ4, while COM2 and COM4 use IRQ3. So in general, if you have two devices, one of which is attached to COM1 and the other to COM3, you cannot use them simultaneously.

Also see the list of IRQ numbers in the Quick Reference section of Webopedia.

(2) Abbreviation of Component Object Model.







TECH RESOURCES FROM OUR PARTNERS
LATEST ARTICLES
SEO Dictionary

From keyword analysis to backlinks and Google search engine algorithm updates, our search engine optimization glossary lists 85 SEO terms you need... Read More »

Slideshow: History of Microsoft Operating Systems

Microsoft Windows is a family of operating systems for personal computers. In this article we look at the history of Microsoft operating... Read More »

Slideshow: Interesting Facts About Google Search

From Goats to Penguins, a server outage and trillions of searches, our slideshow presents interesting facts about Google and the Google.com... Read More »

STUDY GUIDES
Java Basics, Part 1

Java is a high-level programming language. This guide describes the basics of Java, providing an overview of syntax, variables, data types and... Read More »

Java Basics, Part 2

This second Study Guide describes the basics of Java, providing an overview of operators, modifiers and control Structures. Read More »

The 7 Layers of the OSI Model

The Open System Interconnection (OSI) model defines a networking framework to implement protocols in seven layers. Use this handy guide to compare... Read More »