SCSI, Small Computer System Interface, is a set of parallel interface standards used for connecting peripheral devices to computers, it has been widely used for hard drives, tape drives, CD-ROM drives, scanners, printers and other devices. From the past years, SCSI has evolved and diverse into a range of connectors and cables to meet different requirements. This guide covers features, diversity, applications, and how to choose the right SCSI connectors and cables.

Features

1. Speed performance: SCSI connectors and cables are designed to support high-speed data transfer rates, ranging from 5 MB/s (SCSI-1) to 640 MB/s (Ultra640 SCSI).
2. Daisy Chaining: SCSI allows for connecting multiple devices on a single bus, simplifying the overall system configuration.
3. Signal integrity: To maintain signal quality over cable lengths, SCSI uses cable termination at both ends of the bus. This prevents signal reflections that cause data errors.
4. Hot Swapping: Some SCSI standards support hot swapping, which allows devices to be connected or disconnected without shutting down the computer.
5. Multiple device connections: SCSI allows daisy chaining of multiple devices to a single controller, simplifying system setup. Up to 16 devices can connect to a single SCSI channel.
6. Variety of connectors types: SCSI uses a range of parallel connectors from 14pin to 100pin. The wider connectors enable faster data rates. Common connectors include HPCN, HPDB and VHDCI.
7. Flexible cabling: Longer cables: SCSI cables can extend up to 25 meters in length, allowing for flexible device locations.

Applications

SCSI interfaces have been widely used in various applications, such as:

1. Data Storage: SCSI has been a popular choice for connecting hard drives, tape drives, and other storage devices.
2. Optical Drives: CD-ROM, DVD-ROM, and other optical drives have used SCSI interfaces for data transfer and device control.
3. Scanners and Printers: Some high-end scanners, and photo printers also use SCSI interface to computer.
4. RAID Systems: SCSI interfaces have been popular for high-speed data access and redundancy in RAID systems.

Selecting the Correct SCSI connector and cable:

• Interface type: Ensure the connector is compatible with the SCSI interface you are using (e.g., SCSI-1, SCSI-2, Ultra2 SCSI, etc.). Check the specifications of your devices to confirm which interface they use.
• Cable Length: Select a cable length that is appropriate for your setup, keeping in mind that longer cables can introduce signal degradation. SCSI-3 and newer standards generally support cable lengths up to 12 meters, while SCSI-2 supports lengths up to 6 meters. Shielded cables can support longer lengths.
• Cable flex life, Larger conductor gauge wires, like 22 AWG, can handle more flexing than smaller 30 AWG wires. The tighter the bend radius of the cable, the shorter the flex life will be. Cables should be bent with about 6x-10x diameter bend radius to maximize flex life. Generally, SCSI cable flex lives range from around 500 to 10,000 bend cycles, depending on the cable construction and design. Higher quality cables with rugged connectors will typically in the thousands or tens of thousands of bend cycles.

Flexcontac SCSI connector types:

HPCN(High Performance Connector for Networks)： HPCN range from 14pin to 100pin, the 68-pin high-density connector that was used for Fast-Wide SCSI-2 and Ultra2 SCSI interfaces. It has a rectangular shape with two rows of 34 pins and is often referred to as an “MD68” or “HD68” connector.

HPDB(High-Density Parallel D-Subminiature Connector): HPDB is a family of high-density D-sub connectors used in various SCSI interfaces from 20pin to 100pin. The most common types are the HPDB50 and HPDB68 connectors. HPDB50 is a 50-pin connector used for SCSI-1 and SCSI-2 interfaces, while HPDB 68 is a 68-pin connector used for Fast-Wide SCSI-2, Ultra2 SCSI, and Ultra3 SCSI interfaces.

VHDCI(Very High-Density Cable Interconnect): from 36pin to 68pin, a high-density connector used for Ultra3 SCSI and Ultra320 SCSI interfaces. 68-pin count but is more compact than the HD68 connector, making it suitable for applications where space is limited.

SAS (Serial Attached SCSI) connector: SAS is a high-performance interface designed for enterprise storage systems and is often used in data centers and server environments. It is based on the SCSI protocol but uses serial data transmission like SATA. SAS connectors are typically 29-pin connectors (SFF-8482) for internal connections or 26-pin connectors (SFF-8088) for external connections.

SATA (Serial ATA) connector : SATA is a popular interface for consumer-level storage devices like hard drives and solid-state drives. It uses serial data transmission, which allows for faster data transfer rates than parallel SCSI. SATA connectors are typically 7-pin connectors and support one device per cable. SATA is cost-effective, easy to configure, and sufficient for most consumer storage needs. Smaller and more manageable cables.

SCSI has also evolved into a range of connectors and cables to meet different requirements. With various features, applications, and connector types, SCSI continues to play an important role in data transfer and device control. If you need more information, please contact info@flexcontac.com.