HAL Hardware Adapter Layer

HDLC High Level Data Link Control

HDLC-ABM High Level Data Link Control - Asynchronous Balanced Mode

HDLC-NRM High Level Data Link Control - Normal Response Mode

HDN High Density Network

HDWDM High Density Wavelenght Division Multiplexing

HDX Half Duplex

HFT Hands Free Telephone

HFS Hierarchical File System (Macintosh)

HIVITS High Quality Video Telephone System

HLR Home Location Register (GSM) (same as ELN)

HMI Hub Management Interface

HMSC Home Mobile Switching Centre (GSM) (same as CCMN)

HNS Hughes Network Systems

HPLMN Home PLMN (GSM) (same as RMTPN)

HSCSD High Speed Circuit Switched Data

HUBCON Hub Management Console