H

	HA Host Application
	HBA Host Bus Adapter Link host servers or workstations to the storage area network including sub systems and other Fibre Channel devices such as switches, hubs, tape libraries and other servers
	HBFG Host Behavior Functional Group ATM
	HCA Host Channel Adapter
	HCI Host Controller Interface
	HCS Header Check Sequence
	HDBH High Day Busy Hour
	HDD Hard Disk Drive
	HDLC High-level Data Link Control A transmission protocol which embeds information ni a data frame that allows devices to control dta flow and also correct errors.
	HDML

Handheld Device Markup Language

HDSL

High Data rate Subscriber Line

HDT

Host Digital Terminal

HDTP

Handheld Device Transport Protocol

	HDTV High Definition TeleVision
	HEC Header Error Control
	HEP Header Extension Processing
	HFC Hybrid Fiber Coax
	HFW Hybrid Fiber Wireless
	HHP HouseHold Passed
	HID Human Interface Device
	HIPPI HIgh Performance Parallel Interface A standard for connecting two devices together over short distances. The standard version transfers 32 bits at transfer rates of 800Mbps. Wide HIPPI doubles the transfer rate to 1.6Gbps.
	HIS Hi-Speed Internet Service

HLLAPI

High Level Language Application Programming Interface

HPF

High Pass Filter

HPPI

High Performance Parallel Interface

HRC

Harmonically Related Carriers

HSCD

High Speed Cable Data

HSCSD

High Speed Circuit Switched Data

Circuit switched wireless data transmission for mobile users at data rates upto 38.4Kbps

	HSM Hierarchical Storage Management The automatic movement of files from hard disk to slower, less expensive media
	HSM Host Security Module A security module providing the host with a secure environment in which to perform its cryptographic processing.
	HSP Hosting Service Provider
	HSSI High Speed Serial Interface
	HSTM High Speed Transport Multiplex
	HTML Hypertext Markup Language A standard for defining documents with Hypertext links. ( Internet )
	HTTP Hypertext Transport Protocol Underlying protocol used by the World Wide Web. Defines how messages are formatted and transmitted.
	HV High quality Voice
	HW HardWare
	HZ Hertz Unit of frequency equal to one cycle per second.