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
DID YOU KNOW?
5 Best Valentines Day Ideas for Open Source Romantics

Because nothing says "I Love You" Like an open source app. Read More »

Guarding your Data against Cyber Attacks

In this new era of heightened stakes comes an increased need for a comprehensive security strategy. Let's take a look at how cyber-threats have... Read More »

The Great Data Storage Debate: Is Tape Dead?

Tape clearly is on the decline. But remember, legacy systems can hang for a shockingly long time. Read More »

QUICK REFERENCE
Network Fundamentals Study Guide

A network is a group of two or more computer systems or devices, linked together to share resources, exchange files and electronic communications.... Read More »

Computer Architecture Study Guide

This Webopedia  study guide describes the different parts of a computer system and their relations. Read More »

Webopedia Polls

The trend for the past two years has been for shoppers to spend more online during the holiday season. How do you typically shop for holiday... Read More »