Hard-Drive buses OBSOLETE, {Before ATA and SCSI interfaces with hard drives include: XTA, ST506, and ESDI. XTA, XT Attachment. A rarely used implementation of the ATA Interface using an integrated 8 bit XT controller. ESDI [Enhanced Small Device Interface], was a successor to ST506/412 with faster transfer rates and supporting larger drive sizes. The ESDI bus used the same two-cable connection as ST506.}

HDBaseT {High Definition Audio and Video over an RJ-45 connector and 100 meter CAT5e/6 cable. The HDBaseT interface will compete with HDMI starting in 2011.}

H-Bus ("H-Bus is a dedicated input bus designed for transmitting digital media streams from multiple sources to one acquiring host device". The H-Bus was developed by MIT, and operates at 640 Mbps. The H-Bus may have been developed to compete against IEEE-1394 [Firewire], IEEE-1596 [SCI], and Ultra-SCSI.)

HDLC Frame (OSI Layer 2 High-level Data Link Control Protocol Frame description)

HDMI (High Definition Multimedia Interface interface supplies high-definition video and digital audio for consumer Audio Visual entertainment equipment )

HDQ {A single wire open-drain interface to communicate with a battery using a command-based protocol, requiring a passive pull-up resistance is required. The HDQ has maximum transmission rate of 5 Kbits/s}

HIC (IEEE-1355) (Is a bidirectional serial interconnect which builds a scalable parallel system using a pair(s) of unidirectional lines. HIC runs on 1 to 10 Meters cable distance at 38MBps over copper, and with fiber up to 100 to 3000 Meters cable distance at 169MBps, distance depends on fiber type)

HIPPI 'High-Performance Parallel Interface' (Parallel HIPPI operates with a throughput of 200 MBps [HIPPI-1600], up to 25 meters, using copper cabling. Serial HIPPI will run at 200 MBps [HIPPI-1600 Serial] using coaxial cable for distances up to 25 meter, and fiber optic cabling for distances up to 1K meter (Multi Mode) or 10K meters (Single Mode) HIPPI-6400 will run at 1.6Gbps.)

HMVIP Bus {High-Speed Multi Vendor Interface Protocol Bus. May also be H-MVIP}

HPIB Bus {IEEE-488 Parallel Equipment Bus, also called GPIB.}

HSIC Bus {High-Speed Inter-Chip; a chip-to-chip implementation of USB using LVCMOS with a 10cm bus length.}

HSSI Bus {High Speed Serial Interface used for leased lines [like DS3] and Wide Area Networks [WAN]. High Speed Serial Interface Bus specification has a Maximum rate of 52Mbps [bits per second] using differential ECL [Emitter Coupled Logic] over shielded twisted pair [STP] cable (similar to SCSI II) with a maximum distance of 50 feet.}

HSSTP Bus {High Speed Serial Trace Port Specification}

HT Bus (Refer to the HyperTransport Interface)

HTX Bus (HyperTransport eXpansion. The HyperTransport Interface placed on a peripheral slot-based card or interface, HyperTransport on a peripheral card. The current speed of an HTX interface runs at 2.6GHz. HTX motherboards used the same mechanical connector as PCIe, although it's rotated. Also refer to HTX Server Board Manufacturers.)

HubLink Bus (Intel Corp. uses the [proprietary] HubLink [HL] architecture in its Intel 8xx chipsets, as a chip-to-chip interface. HubLink 1.0 was an 8 bit wide bus running at 66MHz. HL 1.5 is 8-bits wide and quad pumped at 133 MHz with a bandwidth of 532 Mbps, and is used to connect the MCH to the ICH. HL 2.0 is 16-bits wide and quad pumped at 133 MHz for a theoretical bandwidth of 1.064 Gbps. The faster HL 2.0 interface connects the MCH [Memory Controller Hub] to the PCI-X and IBA bridges. HubLink is now known as the Hub Interface.)

HyperTransport Bus (A Point-to-Point bus with [at least] two unidirectional links; Uses 2, 4, 8, 16 or 32 bits [in each direction] with a data rate of 800Mbs/per pair with a 400MHz clock. Formally known as Lightning Data Transport (LDT). Used in mobile personal computers, servers, network equipment, embedded applications, and communications equipment)

An alphabetic listing of released interface buses. Primarily the links point to pages that describe the physical and electrical interfaces. Interface Bus protocols are not addressed.