Bus topology uses a broadcast channel. So, all stations have the same priority to transmit data. In this topology use coaxial cable and there are two terminator at the end of the cable. Bus topology uses CSMA/CD (Carrier Sense Multiple Access/ Collision Detection). To transmit data devices need to know that other device is sending a packet on the cable. Bus topology uses a common wire so mean that all PCs on that topology share the data transfer capacity or the bandwidth of that wire.
Star topology uses a central device (Hub/ Switch). Star topology uses CSMA/CD (Carrier Sense Multiple Access/ Collision Detection). Star topology uses more cable than other topology. Although there is a failure in this topology, the entire network can't breakdown. First, data access from the central devices and then distribute other nodes.
Ring Topology
All devices connected in circular fashion. All data transmit in the same direction (either clockwise or counterclockwise). If a device or cable is fail, the entire network is breakdown. Ring topology uses typically FDDI, SONET, or Token Ring Topology.
Mesh Topology
In mesh topology can transmit data any of several paths from source to destination. All devices in mesh topology must connect all other devices and is a complete network. Data transmit with each other by hopping and then reaches its destination node in mesh network.
(b)
(i) Twisted Pair cable
(ii) Coaxial cable
(iii) Fiber - optic cable
(iv) Copper cable
Twisted Pair Cable
In this cable type have two that STP (Shielded Twisted pair) and UTP (Unshielded Twisted Pair)
Advantages
Can transfer data at faster speed because of electrically "cleaner"
Can protect EMI/RFI that is caused near by equipments or wires.
Disadvantages
Can more expensive than other cable
Is difficult to connect to a terminating block
Require peer-to peer connection (straight from one PC to another)
Coaxial Cable
Advantages
Cost is cheaper.
Suitable bandwidth- up to 10 Mbps
Can install easily
Easy to modify and split the signal
Disadvantages
If the amount of frequency is high, the loss is great.
If the cable has long distance transmissions, repeater stations will be amplified and retransmitted weakened signals.
The limitation of frequency rate in coaxial design is about 4 GHz.
Fiber - optic cable
Advantages
It is secure.
There is no electrical interference and low attenuation.
Bandwidth is up to about 54 Mbps
Disadvantages
Cost is very expensive because it needs expensive lasers and receivers at each segment.
If you bend the cable tightly, it can disrupt the signals.
Copper cable
Advantages
Low voltage
It has EMI/FMI (Electromagnetic Interference/ Radio Frequency Interference)
Disadvantages
Attenuation
Crosstalk
Eavesdropping
(c) Recommendation
The customers should use "Star Topology" and UTP (Unshielded Twisted Pair) cable below that
Although one computer is breakdown in Star Topology, network is not filled.
Besides, this topology is easier to manage, locate and expand (cable / workstation).
UTP cable can protect EMI/ RFI (Electromagnetic Interference, Radio Frequency Interference and use in low voltage.
Task 2
Task 2
Investigate the Internet connection requirements for the Fire Department.
Describe the Internet services that may be required.
Explain the connection speeds that are suitable for these requirements
Find examples of Internet Services Providers (ISPs) that can meet these requirements in your country.
Make a recommendation to use one ISP based upon the services offered and price charged.
(a)
Internet Services that may be required
Browsing
Internet e-mail Service
VoIP
Chatting
Browsing
We used browsing services for search information and data. Besides, we can see HTML files, multimedia and E-commerce sites. On the world wide have many fire station site that we can read update information of fire break. We must browse to know update information about Fire and to search about the case of Fire.
Internet e-mail services
In e-mail service have two types, e-mail client (user) and e-mail server. This allows send e-mail, and attaching Postscript documents, Video, Program and other files. Man can connect World Wide Web by e-mail with computerized data, documents and update software. Fire station needed to access the photos of fire break and for staff need graphic design. So, in Fire Department this service is suitable for civilian staff.
VoIP (Voice over Internet Protocol (IP))
Refer to voice calls that traverse networks using the Internet Protocol (IP) rather than the traditional telephone network. This service can improve the communication between staff and need for fire department.
(b)
The fire department need surf the Internet and send via e-mail for their services. So they need the connection speed (512 Kbps) to connect themselves and other people and
- 512 Kbps ADSL
- 512 Kbps Cable
- Up to 400 Kbps Satellite
- Up to 1.5 Mbps Wireless
(c)
In my country have many ISPs that are MPT (Myanmar Post and Telecommunication), Yadanapon. Red Link provides wireless services.
Service Type
Speed
Service providers
Method
Cost
Cable
Up to 50 Mbps
Comcast, Road Runner
Cable and through modem
Approximately
$40 per month
DSL
Up to 20 Mbps
AT&T Yahoo!, Qwest
Local phone provider
Approximately
$40 per month
Wireless
Up to 1.5 Mbps
Clearwire, Verizon wireless, Red Link
With cellular phone tower and PC card
Approximately
1350 FEC
Satellite
Up to 400 Kbps
HughesNet (DirecWay)
Satellite dish or antenna
d) Recommendations
I would like to choose for the Fire Department wireless services that ISPs are Verizon and Red Link. The costs are not very high (approximately 1350 FEC) and no need any phone lines. These services are accessed in anywhere and any place where you would like to surf.
Task 3
Task 3
Investigate the methods the Fire Department could implement for two way voice communications. As a minimum include the following information:
How each method works (frequencies, full / half duplex, etc).
Details of the legal requirements for operating the system in your country (e.g. allocation of frequencies, licensing requirements, etc).
Costs of setting up and operating the system, including licensing costs, equipment costs, etc).
Limitations of each method (interference, range, etc).
Provide a recommendation for how voice communications should be set up and run including reasons for this recommendation.
(a)
In two way voice communication has two types. This is
Half duplex that can't transmit and receive at the same time.
e.g walkie talkie
Full duplex that can transmit and receive (talking, listening and hearing) at the same time.
e.g phone
Walkie Talkie
This is provided by specialized mobile radio services (SMR) for police, taxi and other vehicles. Walkie talkie is handheld device that provides communications between two or more people during dedicated frequencies. In walkie talkie hasn't duplicated procedure and it is used instantly by pressing a button and talking. This can used over short distances and for wide several miles need a repeater. In walkie talkie if you want to talk others, they must hold the push-to-talk button. Their words are converted to radio waves channel (using typically around at frequencies 460 MHz). When the talker is finished, you must release the button and walkie talkie turned to listening mode. In walkie talkie have many series
CLS series (frequencies 56 UHF)
RDX Series (frequencies 89 UHF or 27 VHF, depend on model)
XTN Series (frequencies 56 UHF or 27 VHF)
AX Series (factory programmed frequencies)
Eg
Position
MHz
Bandwidth
1
151.6250 (VHF)
25.0
**22
154.5275 (VHF)
12.5
1
464.5000 (UHF)
12.5/25.0
*3
467.7625 (UHF)
12.5
Mobile Phone
Mobile phones are based on handheld two way radios. According to cellular communication and Internet Association, most people used cell phone. Mobile phone can call anyone at anytime. Most people used mobile phone for various purposes that keep to connect with family, business and to use in emergency case. Mobile phone works with its service network through base station or cell tower by communication. This cell tower divides the signals. In mobile phone need enough power for transmitting and receiving. Mobile phone uses two separate frequencies that one is talking and another is listening immediately. In additional, mobile phone have services and accessories, that is SMS, e-mail, Internet, camera and messaging and players and GPS.
In mobile phone have approximately frequencies around 950 MHz.
Eg.
Input
Output
456.900 MHz
451.900 MHz
449.400 MHz
444.400 MHz
810.1875 MHz
855.1875 MHz
(b)
License requirements for walkie talkie
If their walkie Talkie is FRS radio, there aren't license requirements. If it is GMRS radio channel (Federal Government Regulation), license is required by FCC. The license period of GMRS is five years term. You can renew between 90 days of expiration date. To apply for license, you must fill FCC form 605 manually.
For login you need FCC registration number (FRN) and password. If there aren't password and FRN, you can get by online registration.
Select New and click to continue.
Select service code.
Fill the application.
Make sign your application by your name.
Click Submit.
After submitting the application form, you will receive an Application Confirmation Page with your file number and fee. You will need this page to print for your records. Payment is two types, online by credit cards and mail (including destination address).
Licensing requirements of mobile phone
In mobile phone people paid fee for SIM card to government. Besides, there are monthly bill on phone calls. If you buy a mobile phone, you must apply for the application form. If yours form return, you must make payment for SIM card. Monthly payment depends on phone calls that are local calls, long distance calls and international calls and messages. You must paid monthly bill to the departments concerned with telecommunications.
Equipments for walkie talkie and mobile phone
Walkie Talkie
Mobile Phone
Handset
Handset
Rechargeable battery
Software applications
Recharger
Battery
Audio accessory jack
SIM card
(c) Equipments Costs
Walkie Talkie
Handset
Approximately $ 150
Rechargeable battery
Approximately $ 10
Recharger
Approximately $ 15
Audio accessory jack
Approximately $ 10
Total costs $185
Mobile phone
Handset
Approximately $ 250
Software applications
Approximately $ 20
Battery
Approximately $ 10
SIM card (By government)
Approximately $ 900
Total costs $ 1180 (approximately)
Licensing costs
Walkie Talkie $ 85 ( for 5 years)
Mobile phone
SIM card $ 900
Monthly bill $ 30 (depend on phone calls)
Total costs $ 930 (approximately)
(d) Limitations
Walkie Talkie
Low battery power is the biggest limitation for walkie talkie. (not good for more than 2-3 city blocks)
Only one person can talk at a time.
More easy to eavesdrop.
Not designed for over long distances
Walkie talkie can lose of contact because of high buildings, noise and electric motors.
Mobile phone
Not detect exactly SIM card.
Battery power is lower options.
Noise
Sometimes according to handset problems.
Places, which are buildings, forests and environmental problems.
Range for Walkie Talkie and Mobile Phone
If your Walkie Talkie is license free, you can get about 2 miles.
If your Walkie Talkie is license by GMRS (General Mobile Radio Service ), you can get about 5 miles.
Recommendations
We choose Walkie Talkie because
Walkie Talkie is easy to use and have simple features.
It can work over a decent range (typically 2-4 square miles).
It has long battery life (20 hours 3-4 rechargeable batteries or alkaline batteries).
It has many channels (from about 8 to 25 or more). So you can change to another frequency if other people use walkie talkie nearby.
It is inexpensive.
But
Mobile phone is so expensive.
Can lose contact in some areas and has limited connectivity.
People use mobile phone in driving. So can cause many accidents.
Task 4
Task 4
Investigate telephone systems available in your country for single-site organizations like the Fire Department. Pay particular attention to:
The main equipment that would be installed.
The features available with each system.
The costs of equipment and installation.
The costs of operation the system.
Provide a recommendation for which system to purchase including reasons for this recommendation.
PBXs and KTS
If any company has two or more telephone lines, the company needs to connect them via an ancillary system cable of switching the calls to the various extension lines. For this requirements have two system PBXs (Private Branch Exchanges) and KTS (Key Telephone System). Their most functional terms are the same. But their designs are different. A private Automated Branch eXchange/ telephone exchange linked to the PSTN (Private Switched Telephone Network) and also called the company switchboard.
PBXs
PBXs phone systems are very popular today. This system can expand as extensions grow. There are many wide features and switchboard operators in the PBX telephone system. You can big this system by two factors
Lines that the numbers of phone lines by using
Extensions that every device can connect to the phone system, eg - fax machines, etc.
KTS
Key telephone system is a small telephone exchange for transmitting telephone communications between system and extensions or between extensions and extensions. Key Telephone System can be connected in the few numbers of telephone sets for economically.
The main equipments of PBXs
Internal switching network
Microcontroller or microcomputer for data processing, control and logic.
Logic cards, switching and control cards, power cards
Stations or telephone sets
Console or switchboard to control the operator the incoming calls
Uninterruptible power supply or batteries
Interconnecting wiring
The main equipments of KTS
Central service unit that make as control between incoming lines and telephones.
Station cabling that connect the telephone and central service unit.
Multi - button telephone sets or key telephones that this button provides access or intercom or other features.
Power supply that supply electrical signals to the requirements of system.
The features of each system
The features of these systems based on the equipments of installation. The equipments limited the features of systems.
The Features of PBXs
PBXs provides these features
Auto dialing
Automatic directory services
Blocking
Pick - up
Follow me services
Music
Public address
Messages boxes
Voice mail
Message Broadcasting
The features of KTS
KTS provides these features
Plain Ordinary telephone service (POTS)
Auto - attendant
Music on hold
Memory dialing
VIP- call
The cost of equipment and installation
The costs of equipment and installation for PBXs
PBXs phone system needs to make professional installation and maintenance. The total cost for lager PBXs are approximately between $800 and $2000 per user, including the costs of equipments, installation and maintenance. There have two problems about PBXs that the first is the costs for system up and running speed high. The equipments are limited the features of system. If the costs of equipments are high, the features of system are like that Automatic Call Distribution (ACD) and etc.
The second costs are maintenance and support. The costs of maintenance and support are based on the equipments. The costs of maintenance are 1% of the costs of equipment. Eg-If the costs of equipment are $1000, the costs of maintenance are $100 per month.
Equipments
Costs (approximately)
Microcontroller/ Microcomputer
$100
Logic cards
$300
Telephone set
$150
After the equipments configure, make the process of installation. So, the technician makes the installation of telephone set and wired. The cost of installation is approximately between $100 and $150.
The costs of equipment and installation for KTS
The total costs for key telephone system (KTS) are approximately between $350 and $1000 per use including the installation costs.
Equipments
Costs(approximately)
Central Main Unit
$500
Cable Wire
$70
Telephone set
$150
The telephone set, central unit and cable wire need to install after configuring the equipments. The costs of installation are approximately between $80 and $120.
The cost of operating the system
Costs for KTS
The costs of operating the system in Key Telephone System (KTS) are not required. Key Telephone System is non-programmable and needed for open plain office. But, the maintainable processes that safely the equipment, power supply and wires, are required. So, the costs of maintenance are $50 (approximately) needed per month.
Costs for PBXs
The costs of operating the system in Private Branch Exchange (PBXs) are required. PBXs are suitable with programmable switchboard. Besides, need operator and need to pay phone bill. For the fire department need four operators for saving the power break down and safely security. The costs of operator are approximately $100 per one. So, need $400(approximately). The costs for phone bill are pay for monthly based on your calling times and calling minutes.
Recommendations
The PBXs (Private Branch Exchange) system is suitable for the Fire Department. The PBXs system is easy to install, equipments setting are easy and have many features. Besides, the PBXs system is easy to expand the extensions and easy manage the system. When the calls are entering, the system can search lines rapidly and automatically and communicate these destination lines. Although lines are busy, the system has the simultaneous call facility. The PBXs system is used by forty or fifty employees. In spite of the system have many operators, can safe the system security and reduce the telecommunication costs. The system has less duplication, redundancy and has more reliability. The PBXs system runs by program.
In order to efficiency, calls are more rapidly routed and answered quickly by including auto-attendant.
In order to costs, hardware costs are reduced by standard phones and off-site service.
In order to features, have a lot of features that call forwarding, call dialing and caller ID and etc.
In order to customer satisfactions, can reduce the waiting periods, access accounting information and make appointments themselves.
Because of the above facts, the PBXs system is more suitable for the Fire Department and more available.
Task 5
Task 5
The Fire Department needs to remain operational in the event of a serious incident such as a major terrorist attack or war. Explain the measures you would put in place that would allow the Fire Department to operate in the event of Newtown having no electrical power and fixed telephone lines being broken.
When the accident such as major terrorist or war occur, the Fire Department can occur the failures about that
Line failure
Equipment failure
Power supply and etc.
The Fire Department needs electricity for the purpose of their functions. The communications of the Department is needed to always stand by for the connections with firefighters and the connections with public. At an emergency case, the department receives calls from public, connect with other emergency services when required and contact with firefighters at the accident. For this purposes the department need electricity at every time. But the department has the conditions that the electricity has not the required amount and cut off electricity. In these situations, the department need generator for electricity and connections break down. Besides, UPS (Uninterrupted Power Supply) need for these requirements.
Generator
The generator is required for the needed electricity. It supplies the required amount of electricity to the Fire Department. But the generator must have the required amount of Watt for the Fire Department.
UPS (Uninterrupted Power Supply)
A power supply system that will switch the electricity when the electric power is not sufficient or the electricity cut off. UPS makes the electricity suitable for the Fire Department that adjusts the electric power from the lines or generator.
Besides, the Fire Department requires the BC radio or cellular phone when the fixed phone lines are being broken. This equipments need for the firefighters when the connection breaks down to the control centre or the situations of environments is not connected the communication lines.
Cellular Phone
The cellular phone is lightweight hand portable equipment and has greater network capacity.
When the firefighters of the Fire Department are located in the broken communication environment, cellular phone needs to communicate with the control centre. But the costs of cellular phone are high. So, the only one or two cellular phones can get.
Task 6
Task 6
Create a comprehensive, professional report describing your network recommendations. This should include the details of Tasks 1-5, have estimates cost throughout and have an executive summary at the start giving key points.
The star configuration was the most usual type of configuration initially used in telecommunications networks, both for telephone and computers. So, the Fire Department should be used the star topology for the functions and communications that shows in below
1. Although one computer is breakdown in Star Topology, network is not filled.
2. Besides, this topology is easier to manage, locate and expand (cable / workstation).
3. UTP cable can protect EMI/ RFI (Electromagnetic Interference, Radio Frequency Interference and use in low voltage.
The required speed of the Fire Department is 512 Mbps for the browsing information and data, send e-mail that documents, program, video files and other applications, and voice calls between the staff and control centre. I would like to choose for the Fire Department wireless services that ISPs are Verizon and Red Link. The costs are not very high (approximately 1350 FEC) and no need any phone lines. These services are accessed in anywhere and any place where you would like to surf.
The Fire Department needs to operate two way voice communications. In this communication have two types that full duplex and half duplex. Full duplex is mobile phone and half duplex is walkie talkie.
We choose Walkie Talkie because
Walkie Talkie is easy to use and have simple features.
It can work over a decent range (typically 2-4 square miles).
It has long battery life (20 hours 3-4 rechargeable batteries or alkaline batteries).
It has many channels (from about 8 to 25 or more). So you can change to another frequency if other people use walkie talkie nearby.
It is inexpensive.
But
Mobile phone is so expensive.
Can lose contact in some areas and has limited connectivity.
People use mobile phone in driving. So can cause many accidents.
Besides, the costs of mobile phone and walkie talkie are difference. Mobile phone costs are very high and walkie talkie costs are suitable for the most of company. The costs of walkie talkie for the one firefighter are approximately $300 including license costs and equipment costs.
The PBXs (Private Branch Exchange) system is suitable for the Fire Department. The PBXs system is easy to install, equipments setting are easy and have many features. Besides, the PBXs system is easy to expand the extensions and easy manage the system. When the calls are entering, the system can search lines rapidly and automatically and communicate these destination lines. Although lines are busy, the system has the simultaneous call facility. The PBXs system is used by forty or fifty employees. In spite of the system have many operators, can safe the system security and reduce the telecommunication costs. The system has less duplication, redundancy and has more reliability. The PBXs system runs by program.
In order to efficiency, calls are more rapidly routed and answered quickly by including auto-attendant.
In order to costs, hardware costs are reduced by standard phones and off-site service.
In order to features, have a lot of features that call forwarding, call dialing and caller ID and etc.
In order to customer satisfactions, can reduce the waiting periods, access accounting information and make appointments themselves.
Because of the above facts, the PBXs system is more suitable for the Fire Department and more available.
When the accident such as major terrorist or war occur, the Fire Department can occur the failures about that
Line failure
Equipment failure
Power supply and etc.
The Fire Department needs electricity for the purpose of their functions. The communications of the Department is needed to always stand by for the connections with firefighters and the connections with public. At an emergency case, the department receives calls from public, connect with other emergency services when required and contact with firefighters at the accident. For this purposes the department need electricity at every time. But the department has the conditions that the electricity has not the required amount and cut off electricity. In these situations, the department need generator for electricity and connections break down. Besides, UPS (Uninterrupted Power Supply) need for these requirements.
Generator
The generator is required for the needed electricity. It supplies the required amount of electricity to the Fire Department. But the generator must have the required amount of Watt for the Fire Department.
UPS (Uninterrupted Power Supply)
A power supply system that will switch the electricity when the electric power is not sufficient or the electricity cut off. UPS makes the electricity suitable for the Fire Department that adjusts the electric power from the lines or generator.
Besides, the Fire Department requires the BC radio or cellular phone when the fixed phone lines are being broken. This equipments need for the firefighters when the connection breaks down to the control centre or the situations of environments is not connected the communication lines.
Cellular Phone
The cellular phone is lightweight hand portable equipment and has greater network capacity.
When the firefighters of the Fire Department are located in the broken communication environment, cellular phone needs to communicate with the control centre. But the costs of cellular phone are high. So, the only one or two cellular phones can get.
The Fire Department has included the computer network, the telephone communications and two way communications between the control centre and the fire fighters. Besides, has the connection between the Fire Department and the public.
The star topology is used for the computer network.
Walkie talkie is used for the two way communication.
The PBXs is used for the telephone communication.
Reference;
