Scsi Technical Information, Scsi Basics

2 X 2 SCSI MATRIX SWITCH

6.SCSI Technical Information

6.1SCSI Basics

6.1.1 SCSI-1

The original specification supports data transfers up to 5 MBps on an 8-bit wide parallel data bus. SCSI-1 standards had some incompatibility problems between host adapters and peripheral devices. The need to improve compatibility, increase transfer rates, and add other features for better performance required a review of the specifications.

6.1.2 SCSI-2

Improved compatibility and higher transfer rates were provided in this enhancement. The addition of “Wide SCSI” permits 16 or 32 bits to be transferred in parallel, the latter requiring two cables. In combination with the “Fast SCSI” option, synchronous data transfers up to 10 MBps for 8-bit, 20 MBps for 16-bit, and 40 MBps for 32-bit buses were achieved.

6.1.3 SCSI-3

The most significant additions include the ability to address up to 32 devices, a 16-bit single-cable data bus, and serial SCSI protocol. The SCSI-3 standard has been split into several subdocuments, including the SCSI Parallel Interface (SPI), which is based on a layered protocol, and the SCSI Interlocked Protocol (SIP), a software link protocol.

6.1.4SIGNAL WIRING

The signal wiring used in a SCSI bus has an impact on bus performance. The two wiring techniques generally used for SCSI are single-ended and differential. With single-ended wiring, a single wire carries the signal from initiator to target. Single- ended circuitry is not noise resistant and is generally limited to about 6 meters (20 ft.) at data transfer speeds of 10 MB per second.

Differential wiring uses two wires for each signal and offers exceptional noise resistance because it does not rely on a common ground. This allows cables up to 25 meters (82 ft.) and reliable operation at 10 MB or more per second. Differential wiring and circuitry is more complex than single-ended and generally tends to be more expensive to implement.

SC121A, SC120A-R2 specifications

The Black Box SC120A-R2 and SC121A represent the cutting edge of industrial networking devices designed for robust performance and versatility in various environments. These devices are tailored for applications that require reliable data transmission, making them essential in modern automation and control systems.

One of the standout features of the Black Box SC120A-R2 and SC121A is their advanced serial-to-Ethernet conversion capability. This functionality allows users to connect legacy serial devices to Ethernet networks seamlessly. With support for multiple protocols, including TCP/IP and UDP, these converters ensure smooth communication between devices, regardless of their original architecture.

Both models are engineered to withstand harsh industrial conditions. They feature a rugged construction that includes high-quality enclosures designed for durability and protection against dust, moisture, and extreme temperatures. This resilience makes them ideal for use in factories, transportation, and other challenging environments.

In terms of connectivity, the SC120A-R2 and SC121A come equipped with multiple serial ports, enabling simultaneous connections to various devices. The auto-sensing capability of these ports simplifies installation and configuration, making them user-friendly for both technical and non-technical personnel. Users can easily manage and monitor connections through a straightforward web-based interface.

Additionally, these devices incorporate advanced security features, including encryption and authentication protocols, ensuring that data transmission remains secure from potential threats. This focus on security is crucial for industries where sensitive data is transmitted, enhancing overall system integrity.

The SC120A-R2 and SC121A also support a range of network configurations, allowing for flexibility in deployment. Their compatibility with various operating systems ensures that users can integrate them into existing systems without significant modifications.

Moreover, these models offer flexibility in power options, supporting both PoE (Power over Ethernet) and traditional power supply methods. This versatility enables easy installation without the need for additional power infrastructure.

Overall, the Black Box SC120A-R2 and SC121A are sophisticated networking devices that combine advanced technology with rugged design. Their ability to bridge the gap between legacy serial interfaces and modern Ethernet networks, coupled with robust features and security measures, makes them a valuable asset for numerous industrial applications. Whether in a manufacturing plant or a transportation hub, these devices provide reliable, efficient, and secure communication solutions that meet the demands of today's connected world.