DIY Home Automation at SmartHomeUSA
The focus of this chapter is the computer network as part of the integrated home network. The computer network is perhaps the most critical component in an integrated home network. The computer network is a data communication system allowing a number of independent devices to communicate directly with each other. The computer network connects devices, such as PCs, laptops, printers, servers, scanners. These devices are commonly referred to as nodes. Home technology integrators use cabling, such as Cat 5e, or wireless technology to connect nodes to the computer network. Other, network devices include: repeaters, bridges, switches, gateways, and routers. These devices help direct data flow from one device to another on the computer network.
The computer network provides the digital data access that enables other home subsystems to be linked and controlled throughout the integrated home network. Therefore, it is critical to carefully to take into account some general considerations come when designing and installing computer networks. First among these considerations is the homeowner’s current and future needs. As an integrator, you need to be knowledgeable of industry trends, consider the growth in the homeowner’s family size, and take into account the level of technical experience possessed by the end users. Knowledge of technological trends, the potential growth in the family size, and technology needs of all family members can greatly influence the extent to which potential future needs can be accommodated in the initial design and engineering of the computer network.
Upon completion of this chapter, the Home Technology Integrator or the homeowner will be able to complete the following tasks:
Design a computer network
Install computer equipment for the network
Configure the computer network
Understand how to use the computer network
The material found here is only a part of the complete Chapter 3 of the Home Technology Integration Fundamentals and Certification course offered in its entirety on-line or in print form. For more information about accessing the entire course and the costs involved go to ???????
Define Network’s Scope
The first step in the network design process is to gather the homeowner’s requirements, such as technical and budget, so you can determine what functionality the homeowner needs and can afford. Understanding why the homeowner needs a computer network and how the existing, if any, subsystems such security and lighting, need to be incorporated in the home network is the foundation of the network design. Therefore, before designing a computer network, it is important to understand the functionality required from the computer network by the homeowner.
Determine network services
Some homeowners will be very specific about their requirements. Others will not understand what home networks can offer them. For those homeowners, be prepared to give a small presentation of the possibilities that a home network can provide. The presentation should be tailored to the type of project (retrofit vs. new construction). A customer who is having a new home built will be able to incorporate and install the computer network infrastructure during the electrical phase of construction. As a HTI, you will be invaluable in making sure that all rooms are set up with the appropriate wall jacks and a central location for the router or switching equipment. A homeowner with an existing structure will need to retrofit the infrastructure for a computer network. This process includes running cable through the attic and down the walls. Although this may cause some damage, it is easily repaired and is preferred to running cable along baseboards. A retrofit can also be accomplished with wireless technology. Wireless technology is discussed later in this chapter. It is your job, as the HTI is to make sure that the homeowner is aware of all the options that are available for installing a computer network. Use the following list to determine the homeowner’s network requirements:
Services, such as video, e-mail, Internet, virtual private network (VPN), video entertainment
Single person, couple, family
Security, child protection/control (sensitivity to security issues)
The technical competency of homeowner: a first time or technologically shy user requires a very user-friendly GUI and may need customer support material
Professional needs of parents and educational needs of the kids. E-mail type and volume
Need to share devices: printer, CD-ROM, files, cameras, etc.
Remote access needs: Inside-out or outside-in connection
The management information systems (MIS) contact person for home-to-office connection
Starting at the first meeting with the homeowner, carefully documenting detailed requirements will help you design and install a network that is tailored the homeowner’s needs. Additionally, detailed notes of what the homeowner needs to accomplish and the physical layout of the home will help in the design phase. You will also need to inspect the home to document the physical layout of the home and the existing equipment. The size of the home will affect the cost of wiring as well the placement of devices.
Document customer’s equipment
As a HTI, you will be responsible for ensuring that existing equipment will function on the home network and that it is compatible with new equipment that the homeowner plans for in the future. Understanding these fundamentals will help in determining the location of the wall jacks the cable connections.
Determine location of outlets
The location of existing and future equipment should be discussed with the homeowner. All rooms in a house can be connected in the integrated home. The possibilities are endless. As an HTI, it is up to you to determine the options available based on the location. For more infor ?????
Discuss budget constraints
Most projects will have a limited budget. The homeowner will provide the budget that is allotted to pay for a computer network. It is your job to design a network that fits in with that budget. You may have to explain to the homeowner that they have to choose one feature over another in order to stay within the budget. A computer network typically costs in the range of $1,000.00 â€“ $10,000.00 U.S., depending on its scope. Also, it is important to note that the cost will depend, among others, on the geographic location of homeowner and how much usable equipment exists.
The Reasons to Network
The following sections describe the most popular reasons for choosing to have a home network installed. These reasons will vary with each homeowner but the benefits are obvious. The ability to share files, a printer, and media components saves time and money in the home just as it does in the office. Video surveillance is emerging technology that allows the homeowner to monitor their property. These topics are discussed in the next few sections.
File and print sharing
For the homeowner, there always will be a need to share resources on the home network, such as print and file sharing. These services can be made easier by the presence of some sort of centralized resource location, such as a home server. Luckily, the current residential gateway market trend is the inclusion of a built-in home server. This is typical of most multi-service residential gateways
Data storage is a common practice to any network users. For a home network, this may be the more important in the entertainment and audio/video subsystem, especially if large files have to be downloaded from the Internet to be shared by parents and children. For this reason, a residential gateway with a built-in server having a large hard drive would be preferable.
E-mail and data storage (ISP)
E-mail and data storage service are an important service to the home network users. Many people with high-speed Internet service to their home today tend to want to host their own â€œâ€¦@home” e-mail service. In making a decision to go this route the user has to be well advised about the need for a home server and also the increased security demands that will go with such a service. As mentioned earlier many homeowners do not necessarily possess the type network management skills that will guarantee the security of such a system.
Video surveillance is a common practical use of the residential network. There are many mini digital cameras available today in the market that can be connected to the home network and used for real time monitoring of all or parts of the interior of the residence. The images taken can be stored on a computer and accessed any time. The one big advantage of video surveillance is that the camera can be accessed remotely via the Internet by the homeowner from his/place of work by just a few clicks of the mouse.
A major consideration in designing and installing the computer network has to do with the type of infrastructure technology. The options for the homeowner are wire or non-wire (wireless) systems. The choice of one infrastructure technology over the other is usually dependent upon the type construction (new, remodel, retrofit). Before homeowners can choose an infrastructure, they need to have a clear understanding of what is available.
Wired computer networks use either copper or fiber optic cables to transmit data between two devices. The most common type of network for businesses is Ethernet. There are other types of wired networks available that don’t require running cables in the house. The Phone line system uses existing wiring, namely the phone and power lines. This type of technology is advantageous since no new wiring is needed throughout the home but it does have limitations that will be discussed in a later section.
Wireless solutions are a practical alternative in hard-to-cable areas of an existing home, or for such applications where the portability of computing devices is crucial. However, wireless systems have advantages and disadvantages as shown in Table 3-1.
Ease of installation
Limited signal distance
No ugly wiring throughout the home
Signal interference is a possibility
Computers are portable
Signals are always not secure
Table 3-1 Advantages and disadvantages of wireless systems
Several types of wireless technologies are on the market today, but the three most widely accepted are the IEEE 802.11 Wireless Networking (Wi-Fi), Bluetooth, and HomeRF systems.
Ethernet is a type of local area network (LAN). An Ethernet network is easy to set up in a home that is under construction. In an existing home, it requires running the cable through the attic or having the cable run along the baseboards. The data transmission rate is measured in Megabits per second (Mbps). Ethernet transmits data at a rate of up to 10 Mbps. Newer versions of Ethernet technology are Fast Ethernet, which supports data-transmission up to 100 Mbps, and Gigabit Ethernet, with up to 1,000 Mbps of data-transmission. Ethernet specifications are defined under IEEE 802.3 (the Institute of Electrical and Electronic Engineers standards that are specific to Ethernet).
Ethernet operates on a technology known as Carrier Sense Multiple Access with Collision Detection (CSMA/CD). Each device on the wire listens for data signals that have been transmitted by other devices. If one device has data to send to another device and the wire is clear, it will transmit the data in a special format called an Ethernet frame. If the wire is busy, the device waits until it is clear before trying to transmit.
Phone-Line systems (HomePNA)
Existing telephone wiring is an excellent medium for networking home PCs without adding new wires. The Home Phone Network Alliance (HomePNA) system uses the existing phone line. HomePNA technology uses a method called frequency-division division multiplexing (FDM) to transmit voice and data signals at the same time. FDM works by allocating channels of specified bandwidth and frequency to each signal room, or kitchen.
The main problem encountered with HomePNA systems relate to noise being generated on the cabling and interfering with the data signal. Some sources of noise include analog communication devices (telephones and fax machines using the same wire) or electrical power sources. Adding low-pass filters to the system can mitigate this problem. Such filters transmit the lower frequencies used by telecommunications system while blocking other interfering frequency ranges
HomePNA technology based computer subsystems do not require the traditional Ethernet hub for signal distribution. Instead each PC attached to the phone line network, is provided with a phone network adapter (PNA). These phone line LAN adapters come in external parallel versions or internal Industry Standard Architecture (ISA) or Peripheral Component Interconnect (PCI) bus cards. Leading manufacturers of HomePNA equipment include 3Com, D-Link, Diamond, Intel, and Linksys.
Important considerations for a HomePNA system include:
Only a maximum of 25 networking devices can be on the system.
The cable length between HomePNA devices cannot exceed 500 feet (150 meters).
The overall area of coverage should not exceed 10,000 square feet (1000 square meters).
HomePNA technology may not function properly in residences that use a home private branch-based telephone system (home PBX).
HomePNA works with the majority of existing wiring in homes. In the United States, for example, less than 1 percent of the homes will not be able to use the existing phone line.
Power-Line Carrier systems (PLC)
Power-line is a LAN distribution method that uses the existing power line cabling in the home to send signals to devices. Since most devices in the home, including lights and appliances, draw power form the electrical system, it is possible to communicate with and control these devices through the power system. Power receptacles are already positioned in multiple locations within each room in most homes. As with phone lines, power lines are laid in a bus topology. Typical applications for PLC systems are computer networking distribution, audio/video distribution, telephone distribution, appliance control, security, lighting, HVAC, and energy management control.
X-10 is a communications protocol that allows compatible home networking products to talk to each other via the existing 110 volt electrical wiring in the home. No costly rewiring is necessary. X-10 transmitter devices send a coded low voltage signal that is superimposed over the 110V AC current. Any X-10 receiver device plugged into the household power supply will see this signal. By using X-10, it is possible to control lights and virtually any other electrical device from anywhere in the house with no additional wiring.
In the late 1980s, the EIA (Electronics Industry Association) and the CEMA (Consumer Electronics Manufacturing Association) sponsored the development of a new standard, the Consumer Electronics Bus protocol (CEBus). CEBus is a set of rules for sending messages over electrical wiring, phone lines, coaxial cable, and radio frequencies. A set of specification documents which define protocols for how to make products communicate using power lines, low voltage twisted pairs, coaxial, infrared, RF, and fiber optics. The specifications are free for anyone to develop products from. Few products have yet been developed using CEBus.
HomePlug’s vision is to deliver Internet and multimedia from every home power outlet and to enable the home through worldwide home powerline networking standards. Member companies are building products, primarily Ethernet and USB bridges as of the date of this writing, that seamlessly connect to each other through your customer’s power outlets.
Echelon developed its own protocol, called LonTalk, for automating controls in commercial and residential buildings. Only used in some European residential markets and in some large U.S. homes, its proprietary nature has made some in industry reluctant to embrace it.
Broadband coaxial systems (Series 6)
Coaxial cabling is used to provide cable TV service (known as community antenna television or CATV in the industry). Cable TV providers now offer video programming, telephone service, and high-speed broadband Internet services (requiring a cable modem) to residential customers using the existing coaxial cabling within their homes.
Since each telecommunication service transmits and receives signals at a different frequency, the same coaxial cabling can be used to both distribute television programming and transmit high-speed broadband services.
High Performance Serial Bus â€“ IEEE 1394
Also known as FireWire, the IEEE 1394 is a high performance serial bus standard designed to support high-bandwidth requirements of devices such as digital video equipment and high-capacity mass storage. Supported by the Institute of Electrical and Electronic Engineers (IEEE), the IEEE 1394 standard was developed to meet the need for high data transfer rates between computer components and between the computer components and connected devices such as video cameras. Currently, data-transmission rates of up to 400 Mbps can be achieved, with even higher data rates in development.
IEEE 802.11, Wireless Networking
The IEEE developed the 802.11 standard for systems that are designed to serve as a commercial-grade wireless local area network (WLAN) technology, these systems also have application in the residential environment. This standard is evolving and adapting to meet the needs of the industry as new technology is developed to allow new product designs. The current wireless LAN standard is the 802.11b and offers speeds of up to 11 Mbps. However, there is a wide range of newer versions in the making, all competing to be the successor to IEEE 802.11b. Each to a different extent attempts to address the issues of speed and/or security. Some examples include the IEEE 802.11a (up to 54 Mbps) and IEEE 802.11g (up to 22 Mbps).
The HomeRF Working Group was formed in 1997. The key goal of the group is to enable interoperable wireless voice and data networking within the home at a reasonable price.
A HomeRF is a radio frequency (RF) networking technology that uses a protocol known as Shared Wireless Access Protocol (SWAP). It includes six duplex voice channels in addition to the IEEE 802.11 Ethernet specification for data transmission.
Bluetooth is another industry group developing a specification for low-cost, short-range radio links between mobile computers, cameras, and other portable in-home devices. Bluetooth technology is the result of cooperation between the telecommunications and computer industries. Bluetooth is a short-distance RF communications technology operating for distances of up to 10 meters (33 feet). It enables home networking users to connect a wide range of computing and telecommunications devices easily and simply, without the need to buy, carry, or connect cables.
Bluetooth is intended to be an RF solution in home networking to replace the infrared remote controls used by many devices today such as televisions, video cassette recorders, etc. The technology is being promoted and has been adopted by a group of companies called the Bluetooth Special Interest Group (SIG). They include 3Com, Ericsson, IBM, Intel, Lucent, Microsoft, Motorola, Nokia, and Toshiba
Most of us are familiar with everyday devices that use IR technology such as remote controls for TVs, VCRs, and CD players. IR transmission is categorized as a line-of-sight wireless technology. This means that the workstations and digital devices must be in direct line to the transmitter in order to operate. An infrared-based network suits environments where all the digital devices that require network connectivity are in the one room.
There are, however, new IR technologies being developed that can work out the line of sight. IR home networks can be implemented reasonable quickly; however, people walking across the room or moisture in the air can weaken data signals. IR in-home technology is promoted by an international association of companies called Infrared Data Association (IRDA). www.irda.org