Glossary of Terms - H

Set of instructions for controlling basic modem functions, such as dialling and hanging up, devised by the modem manufacturer Hayes. You probably won't have to know anything about them; your comms program will let you select a plain-English option like "dial now" and will then translate that into the relevant Hayes command code for you.

See High Definition DVD

HD DVD, or High-Definition DVD is a high-density optical disc format designed for the storage of data and high-definition video. The HD DVD disc is designed to be the successor to the standard DVD format, and is derived from the same underlying technologies. It can store about three times as much data as its predecessor (15 GB per layer instead of 4.7 GB).

High Speed Circuit Switched Data. HSCSD allows wireless data to be sent at a rate of 38.4Kbps (kilobits per second) or more, as opposed to a current GSM speed of 9.6Kbps. This is comparable to the transmission rates of usual modems via fixed telephone networks today.

Hypertext Markup Language. HTML is the set of markup symbols or codes inserted in a file intended for display on a web browser page. The markup tells the web browser how to display a web page's words and images for the user. Each individual markup code is referred to as an element (but many people also refer to it as a tag). Some elements come in pairs that indicate when some display effect is to begin and when it is to end.

Hypertext Transfer Protocol. The communications protocol for the web. HTTP defines how information is transmitted across the internet.

Secure version of Hypertext Transfer Protocol (see HTTP)

A device used on a star network to connect all PCs together. When it receives a signal it refreshes and strengthens it before passing it on.

Method of presenting information so users can jump around a document by clicking on a highlighted word or an icon, rather than being forced to navigate it in a linear fashion.