What is I/O Interfaces?,What is IEEE 1394?,What is Parallel to SCSI Converter?,How to test Serial Ports?

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COMPUTER PERIPHERALS AND INTERFACES
I/O Interfaces
An Input-Output (I/O) interface is the piece of equipment or location at which information can be
input and output from a device such as a computer. Examples of an input interfaces are:
Command line, such as a DOS prompt. You manually enter in commands to achieve your results
that you want. The keyboard is also part of this interface.
A GUI (graphical user interface) is an Icon based interface and is much more user friendly and
easier to use. (From a novice stand point) An output interface could be a printer a screen or a
speaker.
Input/output or I/O (or, informally, io or IO) is the communication between an information
processing system, such as a computer, and the outside world, possibly a human or another
information processing system. Inputs are the signals or data received by the system and outputs
are the signals or data sent from it. The term can also be used as part of an action; to "perform
I/O" is to perform an input or output operation. I/O devices are used by a human (or other system)
to communicate with a computer. For instance, a keyboard or mouse is an input device for a
computer, while monitors and printers are output devices. Devices for communication between
computers, such as modems and network cards, typically perform both input and output
operations.
An I/O interface is required whenever the I/O device is driven by the processor. The interface
must have necessary logic to interpret the device address generated by the processor.
Handshaking should be implemented by the interface using appropriate commands (like BUSY,
READY, and WAIT), and the processor can communicate with an I/O device through the interface.
If different data formats are being exchanged, the interface must be able to convert serial data to

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parallel form and vice versa. There must be provision for generating interrupts and the
corresponding type numbers for further processing by the processor if required.
IEEE 1394
IEEE 1394 is an interface standard for a serial bus for high-speed communications and
isochronous real-time data transfer. It was developed in the late 1980s and early 1990s by Apple,
who called it FireWire. The 1394 interface is comparable to USB though USB has more market
share. Apple first included FireWire in some of its 1999 Macintosh models, and most Apple
Macintosh computers manufactured in the years 2000 - 2011 included FireWire ports. However,
in 2011 Apple began replacing Firewire with the Thunderbolt interface and, as of 2014, FireWire
has been replaced by Thunderbolt on new Macs. The 1394 interface is also known by the brand
i.LINK (Sony), and Lynx (Texas Instruments). IEEE 1394 replaced parallel SCSI in many
applications, because of lower implementation costs and a simplified, more adaptable cabling
system. The 1394 standard also defines a backplane interface, though this is not as widely used.
IEEE 1394 provides a single plug-and-socket connection on which up to 63 devices can be
attached with data transfer speeds up to 400 Mbps (megabits per second). The standard
describes a serial bus or pathway between one or more peripheral devices and your computer's
microprocessor. Many peripheral devices now come equipped to meet IEEE 1394.

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IEEE 1394 implementations provide:
 A simple common plug-in serial connector on the back of your computer and on many
different types of peripheral devices
 A thin serial cable rather than the thicker parallel cable you now use to your printer, for
example
 A very high-speed rate of data transfer that will accommodate multimedia applications
(100 and 200 megabits per second today; with much higher rates later)
 Hot-plug and plug and play capability without disrupting your computer
 The ability to chain devices together in a number of different ways without terminators or
complicated set-up requirements
IEEE 1394 provides two types of data transfer: asynchronous and isochronous. Asynchronous is for
traditional load-and-store applications where data transfer can be initiated and an application interrupted
as a given length of data arrives in a buffer. Isochronous data transfer ensures that data flows at a pre-set
rate so that an application can handle it in a timed way. For multimedia applications, this kind of data
transfer reduces the need for buffering and helps ensure a continuous presentation for the viewer.
Parallel to SCSI Convertor

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The Parallel to SCSI Converter lets you attach up to seven SCSI devices to your computer’s
parallel printer port – without having to give up your printer or any performance.
Features and Specifications:
 Connect up to 7 SCSI peripherals without having to give up the parallel printer.
 Plug and Play design – No switches or jumpers to set.
 No need for batteries or an external power source.
 Integrated cable connects directly to your SCSI device.
 Simultaneous operation of all SCSI devices and parallel printer port.
 Mixed SCSI peripherals – Hard Disks, CD-ROMS, MO drives, tape drives.
 Supports all standard SCSI host adapters.

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