H

Half Duplex

The term half duplex is used to describe data transmission that can occur in two directions over the same communications link, in only one direction at a time. Hubs only operate in half duplex mode, as opposed to switches which can operate in both full duplex and half duplex.

Also see Duplex Cable Full Duplex Hub Switch

Header (EDI)

Header (E-Mail)

In E-mail terms, this is the part of the message indicating who the sender is and some other brief details, such as the subject of the message.

Also see Attachments Body E-Mail Signature

hexadecimal color-notation system

The notation system designed to define color values for attributes in HTML documents. The hexadecimal system is based on the RGB (Red-Green_Blue) method for describing color.

Hit

As used in reference to the World Wide Web, "hit" means a single request from a web browser for a single item from a web server; thus in order for a web browser to display a page that contains 3 graphics, 4 "hits" would occur at the server: 1 for the HTML page, and one for each of the 3 graphics.

Home Page

On the World Wide Web, this is the main navigation page owned by a company, organisation, University, individual, etc, from which hyperlinks are made to other pages on the site (or other sites).

Also see Hyperlink

Host

You usually connect to a host computer whenever you use the Internet.

HotJava

A Web browser developed by Sun Microsystems expanding traditional browser capabilities by allowing dynamic functions instead of just static text and images.

Also see Applet Java

HTML

(Hypertext Markup Language). An application of SGML (Standard Generalized Markup Language [ISO 8879]) implemented in conjunction with the World Wide Web to facilitate the electronic exchange and display of simple documents using the Internet.

It is the tagging language used to format Web pages. Allows pictures and text to be combined to create Web documents, and the most important feature - hypertext - making it possible for links to be made between different documents

HTTP

(HyperText Transport Protocol) used on the World Wide Web since 1990, this application-level protocol is essential for the distribution of information throughout the Web.

Hub

A hub serves as a central location for connecting computers and other devices (such as printers) together. A hub is sometimes referred to as a multiport repeater because it passes on, or repeats, all the packets it receives to all its ports.

Also see Packet Repeater Switch

Hyperlink

In World Wide Web pages, hyperlinks are highlighted text or images which, when selected (usually by clicking the mouse button), follow a link to another page. Hyperlinks can also be used to automatically download other files as well as sounds and video clips.

Also see Download

Hypertext

A word or phrase in an online document that is linked to another section of the same document or to a different document. Hypertext words and phrases are usually in blue and underlined.

HyperText Markup Language

See HTML