Transcript Data communications

Data communications
Communication and Networking
Alanoud al Saleh
Data communications
It involves the transmission of data from one
location to another through the use of
pathways which referred to as transmission
or channels.
They include:
-Telephone lines
-microwaves
-radio waves
-coaxial cable
-Satellites
- optical fibers
Communication channels:
The choice of communication channel depends
on several factors, of which data transmission
speed is relatively important.
Data transmission speed depends on band rate
and band width of the communication
channel.
Transmission speed:
Band rate:
Refers to the number of discrete signal
elements (bands) transmitted per sec.
 Band width:
Refers to the frequency capacity of the channel
and is expressed in bits per sec (bps).

Essentials for
Communications:






must have a message
message must have a transmitter
message must have a receiver
Message must have a medium
Message must be understood
Message must have some level of security
Understanding Transmission
Medium
Medium is the physical path between
transmitter and receiver in a data
transmission system
Medium types:
 Conductive: twisted pairs and coaxial cables
 Electromagnetic: microwave
 Light: lasers and optical fibers
 Wireless – inner/outerspace; satellite

Understanding Networking

Networks needs to interconnect at a distance
by a form of point to point or point to multiple
point connected media

A network is a group of computers connected
together in such a way as to allow

Networks that are interconnected have
proven to be low cost, reliable, and efficient
means of communicating at a distance
Key Network Terminology




Node: anything connected to the network, usually a
computer, but it could be a printer or a scanner
Segment: any portion of a network that is separated
by a switch, bridge or a router from another part of a
network.
Backbone: the main cabling of a network that all of
the segment connect to. Usually, the backbone is
capable of carrying more information than the
individual segments.
Topology: The way each node is physically
connected to the network
Network
architecture
Common Topologies - Bus

Bus: each node is chained (connected one
right after the other) along the same
backbone. Information sent from a node
travels along the backbone until it reaches its
destination node.
Common Topologies - Ring

Ring: Similar to a bus network, rings have
nodes chained, but the end of the network in
a ring topology comes back around to the first
node, creating a complete circuit.
Common Topologies - Star

star :In a star network, each node is
connected to a central device called a
hub(host computer ). The hub takes a signal
that comes from any node and passes it
along to all the other nodes in the network.
Network Hardware



Bridge: device to interconnect two LANs that
use the SAME logical link control protocol but
may use different medium access control
protocols.
Router: device to interconnect SIMILAR
networks, e.g. similar protocols and
workstations and servers
Gateway: device to interconnect
DISSIMILAR protocols and servers.
Switches:

Allow different nodes of a network to
communicate directly with each other.

Allow several users to send information over
a network at the same time without slowing
each other down.
WANs and LANs
Major Categories of Networks

Local Area Networks (LAN)
A network of computers that are in the same general
physical location, within a building or a campusare linked
through a topology they create a local area network
(LAN).

Wide Area Networks (WAN)
If the LANs are connected across a region or a wide area
network (WAN) is created when computers are
connected across the county.

Metropolitan Area Networks (MAN)
interconnects a number of (LANs) using a high-capacity
backbone technology and provides up-link services to
WANs and the internet .
Network communication
technology:
LANs, MANs, WANs require a technology that allows
fast communication of the signals. Ethernet is the
common LAN technology
It is based on a bus topology in which computers
share the same cable to send data.
Bit net and internet are other technologies which are
characteristic of WANs.
The internet
The internet
History:
The internet is the largest computer network
system in existence because it connects
users all over the world.
Software was then developed to facilitate the
communication process. This software is
referred to as transmission control
protocol/internet protocol (TCP/IP)
History:
TCP:
Manages the packets and their reassembly.
IP:
Components ensures the packets arrive at their
appropriate remote computers.
History:
In 1990, Dr .Berners-Lee developed the World
Wide Web (www) to facilitate
communications with remote computers
through a set of links. His aim was to
communicate more easily with his colleagues
by linking with their computers.
Major components:
The internet user must first access a server
computer called the internet service provider
(ISP), using a phone line or direct cable
connection. The server computer relays the
user message to the internet. Finally the
internet returns electronic mail (e-mail) or
requested information to the user through the
ISP server.
Web browser:
Allows the user to use a mouse to point and
click on text, drawings and pictures to
facilitate an internet search.
Two popular browser are Netscape and
Internet Explorer.
Uniform resource locator
(URL):
Web sites can be located with a Uniform
Resources Locater (URL) that must conform
to a specific format to ensure successful
communications. The URL is the address of
the site or file on the internet. Example:
http://www.med.harvered.edu/AANLIB/home .html
URL:
-(http://) [hyper text transfer protocol] is the part of the URL
that enable users to access a web page or file include
the protocol for communicating link.
-(www.med.hardvard.edu) or (www.ksu.sa.edu) the ISP
address or domain name.
-The final portion (edu) of the domain name which
demonstrates the type and purpose of the organization.
Search engines:
The internet also features search engines to
help users find information in a systematic
and organized manner. Example of search
engines include Alta Vista, Lycos, Yahoo,
and Google.
Computer in radiology:
In 1955 computers were used to calculate
radiation dose distributions in cancer
patients. Today, computer applications in
radiology include two categories imaging and
nonimaging applications.
Imaging applications:
They are those modalities in which the information
acquired from the patient is subjected to computer
processing. This involves digital image processing
techniques to produce digital images. These images can
be stored or displayed.
Several methods for creating images: computed
radiography, digital fluroscopy, computed tomography
and magnetic resonance imaging.
Imaging applications
Non imaging applications:
Radiology information systems (RIS) patient
admissions, scheduling, accounting, billing, film
library functions, word processing, statistics,
database management and data
communications. RIS can connect to hospital
information system (HIS) which address the
needs of all departments in the hospital
including laboratory, pharmacy, finance,
admissions and hospital administration.
Communication protocol
standards:



Connectivity: refers to a measure of the effectiveness
and efficiency of computer based devices to
communicate and share information and messages
without human intervention. It is achieved by the use of
communication protocol standards.
Protocols: deals with the specifics of how a certain task
will be done.
Standard: it is an approved reference model and
protocol determined by standard setting groups for
building or developing products and services.
Communication protocol
standards:
HIS, RIS and PACs are integrated using
communication protocol standards. The two
popular standards are health level 7 (HL-7)
and digital imaging and communication in
medicine (DICOM).
Communication protocol
standards:

HL-7 : standard application protocol most
used with HIS and RIS.

DICOM : is the imaging communication
protocol for PACs.
Picture archiving and
communications system
(PACS)
An electronic system for archiving,
transmitting, viewing, and manipulating
images is now essential to the digital
radiology department.
PACS:
Wide area network
(WAN)
Communication
Remote
interface
Local area network
(LAN)
RIS/HIS
Display
Control database
system
Computer
monitor
Optical jukebox
or tape
Archiving
CT
MRI
CR
Film printer
Acquisition