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Distinguish between human data input devices and source data capture devices.

Write a note on input and output devices. Distinguish between human data input devices and source data capture devices.
commonly used I/O devices in PC.    

Short for input/output (pronounced "eye-oh"). The term I/O is used to describe any program, operation or device that transfers data to or from a computer and to or from a peripheral device. Every transfer is an output from one device and an input into another. Devices such as keyboards and mouses are input-only devices while devices such as printers are output-only. A writable CD-ROM is both an input and an output device.

Input Devices
a. Keyboard,mouse,joystick,scanners,digital camera, bar code reader, touch Sreeen,Speech input device (microphone)
III. Output Devices
a. Monitor , Speaker, Printers ( different types)
Input/Output devices are required for users to communicate with the computer.
In simple terms, input devices bring information INTO the computer and
Output devices bring information OUT of a computer system.
These input/output devices are
also known as peripherals since they surround the CPU and memory of a computer system.
Some commonly used Input/Output devices are listed in table below.
Input Devices
Light Pen
Touch Screen


II. Input Devices
(a) Keyboard
It is a text base input device that allows the user to input alphabets, numbers and other
characters. It consists of a set of keys mounted on a board.

Alphanumeric Keypad
It consists of keys for English alphabets, 0 to 9 numbers, and special characters like +
−/ * ( ) etc.

Function Keys
There are twelve function keys labeled F1, F2, F3… F12. The functions assigned to
these keys differ from one software package to another. These keys are also user
programmable keys.

Special-function Keys
These keys have special functions assigned to them and can be used only for those
specific purposes. Functions of some of the important keys are defined below.

It is similar to the ‘return’ key of the typewriter and is used to execute a command or

It is used to enter a space at the current cursor location.

This key is used to move the cursor one position to the left and also delete the
character in that position.

It is used to delete the character at the cursor position.

Insert key is used to toggle between insert and overwrite mode during data entry.

This key is used to type capital letters when pressed along with an alphabet key. Also
used to type the special characters located on the upper-side of a key that has two
characters defined on the same key.

Caps Lock
Cap Lock is used to toggle between the capital lock features. When ‘on’, it locks the
alphanumeric keypad for capital letters input only.

Tab is used to move the cursor to the next tab position defined in the document. Also,
it is used to insert indentation into a document.

Function Keys
Numeric Keypad
Cursor Movement
Alphanumeric Keypad/
Special-function Keys

Control key is used in conjunction with other keys to provide additional functionality
on the keyboard.
Also like the control key, Alt key is always used in combination with other keys to
perform specific tasks.
This key is usually used to negate a command. Also used to cancel or abort executing
Numeric Keypad
Numeric keypad is located on the right side of the keyboard and consists of keys
having numbers (0 to 9) and mathematical operators (+ −* /) defined on them. This
keypad is provided to support quick entry for numeric data.
Cursor Movement Keys
These are arrow keys and are used to move the cursor in the direction indicated by the
arrow (up, down, left, right).
(b) Mouse
The mouse is a small device used to point to a particular place on the screen and
select in order to perform one or more actions. It can be used to select menu
commands, size windows, start programs etc.
The most conventional kind of mouse has two buttons on top: the left one being used
most frequently.
Mouse Actions
Left Click : Used to select an item.
Double Click : Used to start a program or open a file.
Right Click : Usually used to display a set of commands.
Drag and Drop : It allows you to select and move an item from one location to
another. To achieve this place the cursor over an item on the screen, click the left
mouse button and while holding the button down move the cursor to where you want
to place the item, and then release it.
Figure 2: The Mouse
(c) Joystick
The joystick is a vertical stick which moves the graphic cursor in a direction the stick
is moved. It typically has a button on top that is used to select the option pointed by
the cursor. Joystick is used as an input device primarily used with video games,
training simulators and controlling robots

Scanner is an input device used for direct data entry from the source document into
the computer system. It converts the document image into digital form so that it can
be fed into the computer. Capturing information like this reduces the possibility of
errors typically experienced during large data entry.
Figure 4: The Scanner
Hand-held scanners are commonly seen in big stores to scan codes and price
information for each of the items. They are also termed the bar code readers.
(e) Bar codes
A bar code is a set of lines of different thicknesses that represent a number. Bar Code
Readers are used to input data from bar codes. Most products in shops have bar codes
on them.Bar code readers work by shining a beam of light on the lines that make up
the bar code and detecting the amount of light that is reflected back

(f) Light Pen

It is a pen shaped device used to select objects on a display screen. It is quite like the
mouse (in its functionality) but uses a light pen to move the pointer and select any
object on the screen by pointing to the object.
Users of Computer Aided Design (CAD) applications commonly use the light pens to
directly draw on screen.
(g) Touch Screen
It allows the user to operate/make selections by simply touching the display screen.
Common examples of touch screen include information kiosks, and bank ATMs.
(h)Digital camera
A digital camera can store many more pictures than an ordinary camera. Pictures
taken using a digital camera are stored inside its memory and can be transferred to a
computer by connecting the camera to it. A digital camera takes pictures by
converting the light passing through the lens at the front into a digital image.

(i) The Speech Input Device
The “Microphones - Speech Recognition” is a speech Input device. To operate it we
require using a microphone to talk to the computer. Also we need to add a sound card
to the computer. The Sound card digitizes audio input into 0/1s .A speech recognition
program can process the input and convert it into machine-recognized commands
or input.

III. Output Devices
(a) Monitor
Monitor is an output device that resembles the television screen and uses a Cathode
Ray Tube (CRT) to display information. The monitor is associated with a keyboard
for manual input of characters and displays the information as it is keyed in. It also
displays the program or application output. Like the television, monitors are also
available in different sizes.
(b) Liquid Crystal Display (LCD)
LCD was introduced in the 1970s and is now applied to display terminals also. Its
advantages like low energy consumption, smaller and lighter have paved its way for
usage in portable computers (laptops).

(c) Printer
Printers are used to produce paper (commonly known as hardcopy) output. Based on
the technology used, they can be classified as Impact or Non-impact printers.
Impact printers use the typewriting printing mechanism wherein a hammer strikes
the paper through a ribbon in order to produce output. Dot-matrix and Character
printers fall under this category.
Non-impact printers do not touch the paper while printing. They use chemical, heat
or electrical signals to etch the symbols on paper. Inkjet, Deskjet, Laser, Thermal
printers fall under this category of printers.
When we talk about printers we refer to two basic qualities associated with printers:
resolution, and speed. Print resolution is measured in terms of number of dots per
inch (dpi). Print speed is measured in terms of number of characters printed in a unit
of time and is represented as characters-per-second (cps), lines-per-minute (lpm), or
pages-per-minute (ppm).

(d) Plotter
Plotters are used to print graphical output on paper. It interprets computer commands
and makes line drawings on paper using multicolored automated pens. It is capable of
producing graphs, drawings, charts, maps etc.
Computer Aided Engineering (CAE) applications like CAD (Computer Aided
Design) and CAM (Computer Aided Manufacturing) are typical usage areas for

(e) Audio Output: Sound Cards and Speakers:
The Audio output is the ability of the computer to output sound. Two components are
needed: Sound card – Plays contents of digitized recordings, Speakers – Attached to
sound card.
Distinguish between human data input devices and source data capture devices.
Data Entry Devices
–   Keyboard entry devices are superior to other devices such as knobs, levers, and thumb wheels.
–   Speed and accuracy are dependent on the quality of data given to the operator, based on the following criteria:
–   The operator is familiar with the format of the information to be entered
–   Upper- and lowercase characters are used for written text
–   Long messages or strings of digits are entered as chunks

–   Messages of the 10 numbers presented in random order are not entered more rapidly than those of the full 26 letters

Chord versus Sequential Keyboards
–   Chord keyboards require activation of one or more keys simultaneously (stenotype machines or pianos)
–   Sequential keyboards are the standard type, where there is a specific key for for each character
–   Chord keyboards are very good for one-handed data entry
–   Chord keyboards are much harder to learn, but tend to be faster.
–   There is no particular need for general-purpose chord keyboards, as sequential keyboards fulfill most requirements
–   For special situations, chord keyboards can be superior
Alphabetic Keyboards
–   QWERTY keyboards were designed to slow the typing process
–   The best alternative was the Dvorak keyboard (Figure 11-19)
–   QWERTY is entrenched in our present society, and is unlikely to change
Numeric Keyboards
–   There are two primary numeric keypads in use today:
–   Calculator Layout
–    Telephone Layout

–   The only differences between the two is for occasional users, who will do better with the telephone layout
Keyboard feel is a combination of a number of characteristics:
•   Key travel
•    Resistance characteristics
•    Auditory activation feedback
•    Hysteresis

–   The feel is often mentioned in product review articles
»   Three keyboards were compared (Table 11–4)
•   The linear-spring keyboard was the least preferred
•   The elastomer keyboards had the fastest times and a low error rate (Figure 11-20)
Membrane Keypads
–   Used in the consumer market, in microwaves, for example
–   Consist of contacts separated by a thin non-conductive layer
–   Key travel is virtually nonexistent
–   To reduce accidental activation, often more force is required
–   The contact areas are often difficult to locate
–   With practice, the keypads become easier to use
–   Three feedback procedures were used to aid the user:
–   Auditory tone, for activation
–   Embossing, for finger-position  
–   Snap domes, to provide both forms of feedback

Split and tilted keyboards
–   Normal keyboards require the hands bend outward (Figure 11-22)
–   This can lead to tenosynovitis and eventually CTS
–   People become accustomed to the designs quickly, and prefer them
Handwritten and Gestural Data Entry
–   The technology has become possible for computers to translate handwriting into computer text
–   At present, it is slow and more error-prone
–   Gestural inputs have been used for text-editing tasks
–   Figure 11- 24
–   When successfully implemented, gestural inputs are faster than those with a keyboard
Cursor Positioning Devices
–   Widespread computer use has made these devices necessary
Touch Screen
–   Use a screen overlay which is interrupted when the screen is touched
–   Easy to learn, but not very accurate
–   Parallax becomes a problem, reducing the effectiveness of the pad
–   Figure 11-25 defines good pad sizes

Cursor Positioning Devices
Light Pen
–   The pen is pressed on the screen, and reads the CRT scanning beam
–   Pointing resolution is better than with the touch screen

Cursor Positioning Devices
Graphics Tablet
–   Position of tablet reduces arm fatigue over a touch screen
–   Digitizing Tablets offer the benefits of a light pen without the fatigue problem
–   Two types of positioning:
–   absolute positA Relative positioning
–   ioning

–   Absolute positioning is faster and more accurate with a small gain
–   Figure 11-26 shows this relationship
–   A lead-lag compensation system gives better speeds with only slightly higher error rates
Cursor Positioning Devices
–   A mouse is easy and fast to use, and it is a relative positioning system
–   A clear space near the computer is required to operate it
Other Cursor Positioning Devices
–    Keyboards
–    Joysticks
–    Trackballs
Cursor Positioning Devices
Comparison of Cursor Positioning Devices
–   There is a tradeoff between accuracy and speed (Table 11-5)
–   The selection of the best device must take into account the relative importance between speed and accuracy
–   The mouse was found to be the fastest and most accurate in a text-editing task
–   In another task, the mouse and trackball were found to be the best
–   Such features as C/R ratio, physical size, and feedback have not yet been systematically investigated

Special Control Devices
–   New devices are replacing standard control devices
–   Teleoperators are remotely controlled devices that augment the physical skills of the operator
–   Today they are used for handling dangerous materials or working in hostile environments
–   Human Factors considerations
–   Lack of physical feedback
–   Deny visual access
–   Often lack binocular vision
–   Time delays for large separations
–   Design of controls for complex effector
Special Control Devices
Speech-Activated Control
–   Advantages:
–   Operator not tied to console
–   Hands are free

–   Applications for Speech Recognition:
–   Data entry occurs simultaneously with other tasks
–   Operator moves around while entering data
–   Well suited for use by the handicapped

Special Control Devices
–   Types of Speech Recognition Systems
–   Speaker independent systems are classed as follows:
–   Speaker dependent
–   Speaker independent
•    isolated-word
•   connected-word
•   continuous-speech

–   These systems are limited, with small vocabularies
Special Control Devices
–   Speaker dependent, isolated-word systems
–   20 to 200 word vocabularies
–   Maximally discriminable vocabularies have a great advantage
–   Each word must be set off with pauses (training required)
–   Systems require 4 repetitions of each word to generate an accurate vocabulary

–   Performance of Speech Recognition Systems
•   Performance of a good system is as good or better than keyboard data entry, although error rates may be higher
Special Control Devices
Eye-Activated Control
–   To date, most eye-control applications have been in the military
–   A helmet is used to track eye movements, and a voice activation is used to actuate the command
–   Accuracy of eye positioning has been found to be ±10 min of Visual Angle in the center of the visual field
Special Control Devices
Disadvantages of eye control:
•    Overburdening of the visual system
•   Control is difficult in a vibrating or accelerating environment
•   Visual distractions can degrade performance
•   Median total activation times of 1.5 to 1.7 seconds
•   Delays inherent in the speech recognition system result in slower    times when voice is used to accept the eye-controlled selection
Data Capture Devices
Data capture devices provide another level of security to prevent critical human error. CI Solutions offers a complete line of data capture tools and products to help you create and manage your identity verification systems.

As technology advances, it becomes easier and easier for people to forge credentials, but data collection devices help prevent this fraud. If you make or use photo badges or ID cards, magnetic strip readers provide an additional form of authentication that is virtually impossible to forge or tamper with. In order to validate the authenticity of a visitor, staff, or employee badge, the data about that person is encoded onto the ID card using the magnetic strip. When they enter your facility, requiring them to scan their ID card in, a magnetic strip reader will validate that the card is genuine. We offer ID card magnetic strip readers, as well as card writers, which imbed the information on the magnetic strip.

Another secure option is digital signature verification using signature capture pads. Access control is based on the verification of a security badge, along with a matching signature that must match the signature put on file at the time the security badge was created. Other secondary verification measures, such as PIN numbers, can easily be forgotten or compromised. But a signature is unique - it is never lost or stolen and is a socially accepted method of verifying identity.

Make your identity verification as secure as possible with these cost-effective solutions.
Data Sheets
Metrologic Orbit Scanner
Metrologic Voyager Scanner
IBC Mag Stripe Reader
IBC Barcode Reader
IBC Barcode, Mag Stripe and Prox Card Reader
Topaz Signature Pad
Snapshell Driver License Scanner
Current Advances
The Electronic Data Capture (EDC) market is highly competitive and different vendors are continually introducing new features to increase market share. The following are the most important advances that are available in at least some products today.
Usability: Most of the benefits of Electronic Data Capture accrue to the sponsor, and often the investigative sites will see no productivity savings compared to filling in paper forms. There is thus a renewed emphasis on providing better web-based data entry capabilities to improve the site experience. This includes easier navigation, rich graphics, calendar controls, field-level validation and guided data entry, such as only displaying a field for “pregnancy status” if the patient is female.
Data loading: It is often helpful for both the investigative staff and the sponsor staff to be able to access all data for the clinical trial patients, not just the data hand-entered through EDC. This could include lab data, IVRS data and patient diary data. Advanced EDC systems offer a way to batch load this data, typically using delimited-ASCII or XML files. These loads will handle both inserts and updates.
Imaging: An increasing number of clinical trials involve images, such as X-Rays, CT scans and MRIs. While the detailed analysis of these high-resolution images is usually done by a separate core laboratory, it can be very useful to attach a low-resolution copy of the image to an appropriate form in the EDC system. This can aid status tracking and problem resolution, such as differentiating between images taken around the same time. The ability to attach images can also be extended to attach other types of file, such as Excel spreadsheets, PDFs and digital ECG traces.
Integration with other systems: The data in an EDC system is often needed on a real-time basis by related systems, such as those performing randomization, tracking clinical supplies or managing investigator payments. Building integrations between these systems therefore provides extra value and efficiency. The most sophisticated of these integrations interact via web services, and exchange information using the CDISC ODM standard.
SDTM datasets: A second CDISC standard called the Study Data Tabulation Model provides a specification on how data should be presented for analysis. The FDA is requesting data in this format to speed the approval process. Producing SDTM datasets from an EDC database is a complex and time-consuming exercise, so some EDC vendors are providing mapping tools that automatically generate SDTM datasets and remove the need to write and validate study-specific programs. These tools can save many weeks of effort at the end of a study.
Statistical monitoring: In August 2011, the FDA issued a draft guidance on establishing a risk-based approach to monitoring. One part of this document states that it is not necessary to perform Source Document Verification (SDV) on 100% of the forms in the study, provided that the selection of forms is managed as part of an overall monitoring plan. Some Electronic Data Capture systems therefore offer a capability to automatically select a subset of forms to monitor, based on a pre-specified statistical algorithm. This can significantly cut clinical trial costs by reducing the number of monitoring visits to the site.
Future Advances
The following advances are on the horizon, but are generally not available today due to a lack of standards and/or the newness of the technology.
Standard Edit Check Syntax: The design of a study involves the specification of the form and visit structures, as well as the programming of what are known as “edit checks”. These includes data validations, such as checking a start date is earlier than an end date; conditional navigation; data derivations such as calculating age from data of birth; and object creation, such as generating forms for a new treatment cycle if the prior cycle showed no response. While the specifications for the form and visit structure are part of the CDISC ODM standard, there are no standards for the specification of edit checks. This means that each vendor supports a proprietary mechanism, making study designs non-portable between different EDC systems and sometimes leading to a skills shortage in a particular product. An industry-standard approach to edit checks would resolve both issues.
EMR interfaces: Increasingly, much of the source data for a clinical trial is already captured in the Electronic Medical Record for the patient. Unfortunately the state-of-the-art for Electronic Data Capture systems is to make the site staff type the data in again, as there are few if any integrations with EMR systems. The challenges are the wide variety of different EMR systems, concerns over system validation, and slow adoption of appropriate standards such as HL7 version 3. Nonetheless, the industry is expected to make progress in this area, starting with targeted pilot projects to prove technical feasibility.
Mobile: The typical device for using an Electronic Data Capture system is a laptop or desktop computer, connected to the Internet via a web browser. Adoption of mobile devices such as tablet computers or smartphones is fragmentary. While it is technically possible to launch a browser such as Firefox from a mobile device and access an EDC application, the screens are typically too congested and the icons too small to be convenient for touch-screen access. Therefore the industry needs to develop specific apps for accessing EDC from mobile devices. This would support both staff at the investigative site, who could now potentially enter data at the patient’s bedside, as well as patients themselves entering their own data, such as pain levels at various times of the day.

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