Black Box Explains...SCSI-1, SCSI-2, SCSI-3, and SCSI-5.
Product Data Sheets (pdf)...Ultra2 LVD SCSI Cables and Terminators
There are standards
and there are standards applied in real-world applications. This Black Box Explains illustrates how SCSI is interpreted by many SCSI manufacturers. Think of these as common SCSI connector... more/see it nowtypes, not as firm SCSI specifications. Notice, for instance, theres a SCSI-5, which isnt listed among the other approved and proposed specifications. However, for advanced SCSI multiport applications, SCSI-5 is often the connector of choice.
Supports transfer rates up to 5 MBps and seven SCSI devices on an 8-bit bus. The most common connector is the Centronics® 50 or a DB50. A Micro Ribbon 50 is also used for internal connections. SCSI-1 equipment, such as controllers, can also have Burndy 60 or 68 connectors.
SCSI-2 introduced optional 16- and 32-bit buses called Wide SCSI. Transfer rate is normally 10 MBps but SCSI-2 can go up to 40 MBps with Wide and Fast SCSI. SCSI-2 usually features a Micro D 50-pin connector with thumbclips. Its also known as Mini 50 or Micro DB50. A Micro Ribbon 60 connector may also be used for internal connections.
Found in many high-end systems, SCSI-3 commonly uses a Micro D 68-pin connector with thumbscrews. Its also known as Mini 68. The most common bus width is 16 bits with transfer rates of 20 MBps.
SCSI-5 is also called a Very High-Density Connector Interface (VHDCI) or 0.8-mm connector. Its similar to the SCSI-3 MD68 connector in that it has 68 pins, but it has a much smaller footprint. SCSI-5 is designed for SCSI-5, next-generation SCSI connections. Manufacturers are integrating this 0.8-mm design into controller cards. Its also the connector of choice for advanced SCSI multiport applications. Up to four channels can be accommodated in one card slot. Connections are easier where space is limited. collapse
Black Box Explains...Solid vs. stranded cable.
Product Data Sheets (pdf)...PC to Printer Cables
Solid-conductor cable is designed for backbone and horizontal cable runs. Use it for runs between two wiring closets or from the wiring closet to a wallplate. Solid cable shouldn’t be... more/see it nowbent, flexed, or twisted repeatedly. Its attenuation is lower than that of stranded-conductor cable.
Stranded cable is for use in shorter runs between network interface cards (NICs) and wallplates or between concentrators and patch panels, hubs, and other rackmounted equipment. Stranded-conductor cable is much more flexible than solid-core cable. However, attenuation is higher in stranded-conductor cable, so the total length of stranded cable in your system should be kept to a minimum to reduce signal degradation. collapse
Black Box Explains...RS-232.
RS-232, also known as RS-232C and TIA/EIA-232-E, is a group of electrical, functional, and mechanical specifications for serial interfaces between computers, terminals, and peripherals. The RS-232 standard was developed by... more/see it nowthe Electrical Industries Association (EIA), and defines requirements for connecting data communications equipment (DCE)—modems, converters, etc.—and data terminal equipment (DTE)—computers, controllers, etc.) devices. RS-232 transmits data at speeds up to 115 Kbps and over distances up to 50 feet (15.2 m).
The standard, which is functionally equivalent to ITU V.24/V.28, specifies the workings of the interface, circuitry, and connector pinning. Both sync and async binary data transmission fall under RS-232. Although RS-232 is sometimes still used to transmit data from PCs to peripheral devices, the most common uses today are for network console ports and for industrial devices.
Even though RS-232 is a “standard,” you can’t necessarily expect seamless communication between two RS-232 devices. Why? Because different devices have different circuitry or pinning, and different wires may be designated to perform different functions.
The typical RS-232 connector is DB25, but some PCs and other data communication devices have DB9 connectors and many newer devices have RJ-45 RS-232 ports. To connect 9-pin PC ports or RJ-45 to devices with 25-pin connectors, you will require a simple adapter cable. collapse
Black Box Explains...IEEE 1284
Introduced in 1994, the IEEE 1284 standard addresses data-transfer speeds and distance for parallel interfaces. Standard parallel interfaces support speeds of up to 150 kbps at distances of up to... more/see it now6 feet (1.8 m); IEEE 1284 parallel interfaces can send your data over 100 times faster at up to five times the distance!
Although the Centronics® interface enabled only unidirectional computer-to-peripheral data flow, the IEEE 1284 interface enables bidirectional flow so peripherals can send data to the computer.
The IEEE 1284 standard covers five separate parallel modes, from the original Centronics (with which it’s compatible) to the high-performance Enhanced Parallel Port (EPP) mode. The computer negotiates with the attached device to determine which mode to use. collapse