Very High Density Cable Interconnect

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What Does Very High Density Cable Interconnect Mean?

A Very High Density Cable Interconnect (VHDCI) is an improved type of SCSI hardware used as an external connector for SCSI cables and devices. The SCSI interface is a set of standards that transfers data and physically connects a computer and a peripheral device.


The VHDCI is defined as an SPI-2 standard and is a smaller version of the older high-density 68-pin connectors. It was introduced in the SPI-3 document of SCSI-3. The SCSI-3 is the third generation of SCSI; a standard that introduced Fast-20 and Fast-40 and includes high-speed serial bus architecture such as IEEE 1394, Fibre Channel, and Serial Storage Architecture (SSA).

The benefit of VHDCI is that it is very small. Two connectors can be crowded next to each other inside the width of a SCSI host adapter’s back edge or expansion slot insert. This allows the placement of four wide SCSI connectors on the back of a single Peripheral Component Interconnect (PCI) card slot.

Techopedia Explains Very High Density Cable Interconnect

VHDCI connects UltraSCSI and other SCSI peripheral devices. It is an extremely miniaturized connector that is comparable in architecture to the Centronics connector. It is in correlation with the SPI-3 document of SCSI-3, which supports a 16-bit bus and has data rates of 40 megabytes per second (MBps).

The SCSI is a parallel interface standard used to attach peripheral devices to computers. The SCSI supports a faster data transmission rate compared to the standard parallel or serial ports. Additionally, several devices can be connected to one SCSI port.

The VHDCI cable is utilized by various companies, including:

  • Nvidia: The cable is used as an external Peripheral Component Interconnect Express (PCI Express) with an 8-lane interconnection. Additionally, it is used in Nvidia’s Quadro Plex Visual Computing System (VCS), designed for large-scale 3D visualization.
  • ATI Technologies Incorporated: Used on the FireMV 2400 graphics card to transmit two Video Graphics Array (VGA) and two Digital–Visual Interface (DVI) signals on one connector. Two of the VHDCI connectors next to each other create the FireMV 2400 to exist as a low-profile quad display card.
  • Juniper Networks: Used as a connector for the 12-port and 48-port 100Base-TX Physical Interface Cards (PICs) using a registered jack-21 (RJ-21) and RJ-45 patch bay.

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Margaret Rouse
Technology Expert
Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.