How to Choose the VHDCI Cable? (Source: Bespokecable)

How to Choose the VHDCI Cable? The Complete VHDCI SCSI Cable Buying Guide

Shenzhen, China (PRUnderground) July 23rd, 2026

Even though everybody uses SATA and SAS, and USB now, the VHDCI cable (Very High Density Cable Interconnect) is still found in lots of places, like e.g., instrument test and measuring equipment (DAQ), factory and industrial testing and measuring (testing and measuring), RAID storage arrays, and legacy server environments, etc. Selecting the right VHDCI SCSI cable is important when connecting a National Instruments DAQ card, an LVD-SE SCSI host bus adapter, or an external tape library (otherwise, you may experience poor signal integrity or other compatibility issues).

This buying guide for VHDCI cables provides engineers, IT professionals, and purchasing teams with a reference guide to assist them when choosing the correct Complementary

Network Solutions VHDCI cable to meet their requirements for connector types, shielding, wire construction, and SCSI standards. Browse our complete line of Computer & Industrial Cables, such as SCSI Cable, IDC Cable, D-Sub Cable, Flat VGA Cable, Camera Link Cable, DIN Cable, and PCIe Riser Cable.

1. A VHDCI Cable – Where is it used?

The name of this cable dates from “Very High Density Cable Interconnector”. It is available in 68-pin and 100-pin versions, and the cable is almost half the size of the traditional SCSI HD68 Cable. The introduction of VHDCI cables broke the standard for SCSI cables, as dual SCSI-3 cards became popular for large files, with users storing much more information on servers due to greater bandwidth availability. Dual SCSI-3 cards became almost standard, as did PCI/PCIe cards.

VGA monitor cables are usually analog. The analogy of a VGA cable shows that there is a significant difference in shielding and quality among various cables for VGA and VHDCI. (The better the quality of the two VGA cables, the better one’s experience will be.) A high-quality (68-pin) VHDCI cable will be constructed with individually twisted-pair and braided-shield configurations, along with individual strands of 30- or 28-AWG conductors. This was done to ensure that each vendor adhered to the approved manufacturing specifications for impedance and crosstalk in high-speed SCSI bus environments.

In most cases, the first step in choosing the right VHDCI cable for DAQ or SCSI is to identify the gender and mating interface of the connectors on both your host adapter and target peripheral.

2. VHDCI 68-Pin vs HD68(MDR) SCSI Connector Difference

The two types of SCSI connectors that are frequently confused by consumers are VHDCIs (i.e., the 68-pin version) and HD68 (i.e., MDRs). The SCSI-3 signal set is the same for both connections, i.e., 68 pins. However, except for that, there are some differences between the two:

• VHDCI (VHDCI 68/SCSI-5): Compact, 0.8 mm pitch connector with offset orientation for easy compatibility with multi-port HBA cards. The VHDCI is commonly seen on many NI DAQ cards, Adaptec/LSI Ultra320 HBA’s, and high-end oscilloscopes.
• HD68 (Hal-Pitch D 68/MDR 68):​ has a larger form factor and a 1.27 mm pitch. This connector was traditionally used for connect to external SCSI-3 ports on older RAID arrays, tape drives, and scanners.
• HPDB68/Centronics 68: Also known as “Micro-DB68” or “Centronics 68”, this is yet another unique form factor typically found on older SCSI disk arrays.

Knowing the difference between these two connectors will help you determine whether you need a VHDCI-to-VHDCI cable or a VHDCI-to-SCSI cable (which would be something like a VHDCI-to-HD68 or VHDCI-to-HPDB68).

3. VHDCI to VHDCI or VHDCI to HPDB68 – Which Do I Need?

When choosing between VHDCI-to-VHDCI or VHDCI-to-HPDB68 cables, you need to consider both sides of your signal chain.

• VHDCI Male-to-Male (VHDCI to VHDCI): Use this cable if both the Host Adapter (e.g., an NI PXI DAQ module) and your Target Device (e.g., a Breakout Terminal Block with a VHDCI port) are fitted with 68-pin VHDCI Female Receptacles. This cable is the most suitable VHDCI cable for National Instruments DAQ Card Setups.
• VHDCI to HD68: This is the most common application, connecting a contemporary HBA with a VHDCI port to an external SCSI enclosure via the old HD68 port.
• VHDCI to HD68/Centronics 68: Use this type of SCSI cable when your peripheral device has a Centronics-type SCSI connection (Centronics stands for Old-Style 68-pin SCSI) rather than the newer HD68 SCSI connection.

Make sure you have the right combination of male/female ends on your cable; most external SCSI cables will have male ends on both ends, while internal ribbon cables will have female headers on all ends.

4. How can I find out if my device has a VHDCI 68-pin port?

Generally, to verify whether your device has a VHDCI 68-pin port, examine the physical connector on the card or instrument faceplate. The VHDCI connector measures approximately 16mm by 10mm and has two rows of pins, each containing 34, for a total of 68 pins. These ports are commonly identified as “VHDCI”, “SCSI-5“, or the 0.8 mm pitch symbol. When you compare it to an HD68 port, you can see that the VHDCI port is much thinner. If the label is unclear, you can refer to your device’s hardware manual for an I/O diagram.

5. Can You Connect Ultra320 (VHDCI) Cables To SCSI Devices?

A frequently asked question from system integrators concerns whether a VHDCI cable can support Ultra320 SCSI data transfer rates. The answer is yes, but only if the cable conforms to the Ultra320 LVD (Low-Voltage Differential) standard. An Ultra320-compliant SCSI VHDCI cable provides transfer rates of up to 320 megabytes per second and is constructed with twisted-pair cables that are impedance-matched and backward-compatible with Ultra160, Ultra2, and Wide SCSI devices.

The use of substandard or non-twisted-pair cable with an Ultra320 bus can result in a controller negotiating to slower speeds and/or exhibiting CRC errors. You should always confirm the SCSI standard for which a particular cable has been tested before buying a cable.

6. VHDCI Cable Pinout and Wire Pairing — The Importance of Twisted Pairs

Knowing the VHDCI cable pinout and the twisted-pair wiring is essential for successful operation. Twisted pairs and braided shielding are used to reduce crosstalk and electromagnetic interference (EMI) and to transmit data successfully. The wires are connected as closely as possible to maximize their effectiveness for this purpose.

Many budget cables lack adequate shielding and/or proper conductor pairing, which can cause intermittent connectivity issues in many applications, but it is especially problematic in industrial settings with high electrical noise. Be sure to request a pinout or wiring diagram from your cable vendor. In most external SCSI applications, straight-through wiring is used; however, many Proprietary DAQ applications require a special crossover cable.

7. Comparing VHDCI Shielded Cable and Unshielded Cable in a Noise Environment

If your lab or factory floor has noise, do not even consider using an unshielded cable. A shielded cable will be your best choice, with double- or triple-shielded cables being the chief candidates. Most high-quality 68-pin VHDCI cable assemblies will have the following features:

• Aluminum foil shielding around every twisted pair or group OF PAIRS;
• Overall, tinned copper braid shielding.
• A 360-degree metal back shell/overmold bonded to each shield, which provides for complete EMI suppression.

Cables with no shield or a minimal shield will work for short distances in a clean EMI environment. but are not recommended for use in industrial automation, near motor drives, or in rack rows with high RF noise levels.

8. Cable Length Limit and Signal Attenuation (SCSI-3)

Yet another key point is the cable length limit and the signal attenuation of the VHDCI (SCSI-3). Based on the number of devices and the type of signaling used (Single-Ended vs. LVD), the SCSI-3 specification has set a maximum total bus length, which is as follows:

• LVD (Ultra160/Ultra320): maximum permissible bus length of 12 meters (39ft approx.) for all devices on the bus; individual cable runs will be generally between 1 and 3 meters.
• Single-Ended (SE): the maximum permissible total bus length is 6 meters (20 ft., approx.), and shorter cable segments are recommended.

If you go beyond these distance limitations, signal degradation over distance creates additional reflections and reduces the available noise margin for generating a successful signal. For runs near the maximum defined length, use the best-quality, low-capacitance cable with properly shielded cables and properly terminated buses at both ends of the cable.

9. Connector Hardware includes Jackscrews, (Offset) Orientation, and Plating.

Quality VHDCI cables are assembled with jackscrews and thumbscrews on both sides of the connectors, allowing the cable to be secured to the chassis in vibration-prone environments and helping prevent accidental disconnection and data corruption.

Due to the fact that PCI/PCIe slots are placed in close proximity to each other, most host adapter cards require the use of offset VHDCI connectors, which are connectors where the body of the connector is located at an offset from the flange – this allows the use of multiple cables plugged in next to each other. The offset orientation must be confirmed prior to order placement.

The gold flash, or 15µ′- 30µ′ gold plating, offers improved corrosion resistance and low resistance in 68-pin/100-pin VHDCI connectors for multiple mating cycles. This is a very worthwhile upgrade for DAQ benches with multiple reconfiguration cycles.

10. Selecting the Best VHDCI 68-Pin Male to Male Cable to Connect Your RAID Controller to Your RAID Enclosure

For a typical server admin who needs to connect an LVD Ultra320 HBA to an external RAID shelf (many of which have matching external VHDCI ports), the best cable for the application is a VHDCI 68-pin male-to-male cable that connects your RAID controller to your RAID enclosure. Cabling between your controller and your external storage should be available in 0.5 m, 1 m, 1.5 m, and 3 m lengths to allow you to create a clean cabling path without excess cable. The enclosure’s SCSI ID termination method needs to be checked to ensure it is properly configured.

If your RAID Enclosure uses HD68, you’ll need the VHDCI-to-HD68 version (still a VHDCI-to-SCSI Cable, but with mixed Connectors).

11. Final Selection Checklist

Do a quick check before submitting your order:

• Check if the host and device connectors are VHDCI 68-pin, HD68, and HPDB68/Centronics 68
• Confirm both connectors are male (external = male, both ends)
• Check for backward compatibility with Ultra320 cables, as older standard cables can be a bottleneck on new HBAs
• Select twisted-pair, double-shielded cables with 360-degree protective backshells.
• Use the smallest length that can still be routed cleanly
• If connecting to a multi-port HBA, select offset VHDCI orientation.
• Check that the connectors have jackscrews or thumbscrews and gold-plated contacts.

You will not have the most common issues – bent pins (on the DB-15 (D-sub 15 pin)) VGA family, wrong SCSI heads, or noisy analog ghosts, and you will also ensure your VHDCI cable buying guide provides you with strong and high-speed data transfer.

If you’re searching for VHDCI 68 pin cable for a test system from national instrument, or a cross standard VHDCI to SCSI cable for use in restoring legacy tape backup systems, or just learn more about the form factor known as Very High Density Cable Interconnect, the investment made in having the correct type of assembled product can provide the maximum amount of uptime and accurate test and measurement results.

Visit Bespokecable.com for an entire line of accurately engineered cables that will offer excellent performance, i.e., SCSI and Industrial Cables, to engineering professionals looking for signal quality.

About Bespokecable (VHDCI Cable)

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