Twenty-first century communication systems need to carry voice, data, video (V/D/V) and controls information. More people and machines are talking to each other using more kinds of systems than ever before in the history of the world. The greater the number of systems we have, the more varied and complex are the means for having them interconnect. The systems need to talk to each other over a connected information highway that can deliver information at high speed and without distortion. There is no doubt that in the coming years there will be a continuing demand for ever-increasing quantities of data at ever-increasing speeds. There is a widely held belief that the increased use of wireless and fiber optic technology will render copper wire obsolete. Nothing could be further from the truth-every wireless link added to an information system means added copper. Even if fiber optic cables sometimes replace copper in certain parts of the network, the end points will still be copper. The bottom line is that that the more the information highway grows, the more uses there will be for copper wire.
Places and Pathways for Information and Control
Places where information and control systems function:
- Within a building (including some outdoor areas such as driveways, lawns, swimming pools and perimeter fencing)
- Outside of a building (the entire outside world)
- Connecting between inside and outside
Pathways for information and control:
- Person-with-person
- Person-with-machine
- Machine-with-machine
These places and pathways strongly influence the kinds of connections that are used. Connections are by wire, wireless transmission and fiber optic cable. Any system in the outside world, or that connects to the outside world typically uses a combination of all three media. The balance between the media should be decided by issues such as what's best for the user: the quantity of data to be transmitted, desired quality of the transmission, the amount of time-lag that can be accepted, the distance of the transmission, convenience and flexibility of the installation, and making use of the already installed infrastructure. The final determination comes down to weighing cost versus benefit.
Networking within a Home
There are a growing number of systems that can be integrated to make homes safer, greener and more comfortable. The more subsystems that are integrated, the more important it is that the home should have a network running on a hardwired backbone. A hardwired home area network (HAN) should be laid out in a star configuration, in which every room is connected by a wire run back to a central point. The wires should be a minimum of CAT 5e unshielded twisted pair (UTP), but for best future-proofing, CAT 6 is preferable. If the system is wired with CAT 6 cable, each separate connection will be capable of transferring data at a rate of up to 1 gigabit per second, for a distance of up to 100 meters (328 feet). This is more than enough distance and throughput for most homes. Although it's not guaranteed, most CAT 6 cable will even work at 10 GB per second up to 50 meters (164 feet). One gigabit, however, should be more than adequate to run any devices over Ethernet in the home, including multiple HDTVs, Blu-ray, multi-channel audio, surveillance cameras, lighting controls, access controls, intrusion alarms, temperature controls, and power grid connections for smart metering and control of appliances.
Wireless Connections at Home
Wireless connections in the home area network can be divided into two general types.
- A radio frequency (RF) Wi-Fi network connected to the wired home area network (HAN) through a wireless access point (WAP).
- Direct point-to-point RF wireless connections between devices, using protocols like Zigbee or Z-wave.
(1) A wireless access point in each room is a desirable part of any Ethernet-connected HAN. They're very handy for devices that you don't want to tether to a fixed connection, for example, a laptop or two (or three). Wireless connections are often used to connect one laptop to others, to a printer, to the Internet. But the printer has to be hard-wired to a power supply, as does the charger for the laptop's batteries and the Internet modem.
Some audio systems use the WAP in each room to conveniently connect remote speakers, perhaps mounted on the ceiling. Any of the various Ethernet-connected audio sources can then be selected to play through the speakers in any room.
(2) Point-to-point wireless connections have a variety of uses, for example to gather information from home-health sensors, such as temperature, humidity and ambient light levels. Then there are sensing devices like intrusion detectors on doors and windows and fire-detection sensors that connect to alarm systems. Although for maximum reliability, the most important sensors such as those for fire, smoke or gas should be hard wired into the network. Point-to-point wireless is also useful for remotely controlling lighting. Of course there are also the ubiquitous remote controls for the TV, the DVR, the audio system. The latest development is using portable tablet PC devices like the Apple iPad or the Kindle Fire as an advanced universal remote control. But the key word is control- the actual video or audio content can only reliably be hard-wired.
All of these converged systems, including both the wired and wireless components are connected to the same network and can be operated from a user interface, on a TV screen, touch-screen or computer. The user interface can transmit commands and display status by connecting to the wired/wireless network through a central controller.
POE (Power Over Ethernet)
One of the great advantages of wired Ethernet is that at the same time as it is carrying data, it can also carry dc power. The IEEE standard governing the Ethernet was amended in 2009 (IEEE 802.3at-2009) to increase the allowance for dc power carried over Ethernet on UTP cable from 15.4 watts (PoE) to 25.5 watts (PoE plus). This power can be used to operate devices like VoIP telephones and IP surveillance cameras. One of its most useful features is that it can provide power to operate wireless access points-another important example of wired and wireless networks supporting each other.
The Outside World
The outside world is interconnected by a maze of information transmission systems, for example, land-line telephones, cellular telephones, Internet, cable TV, video, audio, wireless RF transmission over earth-based microwave links and via satellite. Each of these uses a combination of copper, wireless and fiber optic connections. Each particular system can consist of any number of separate legs, called hops. The terminating point of a hop is a node, which is a point at which different networks can exchange information with each other. The means for passing information from one network to another at a node is an electronic device called a router. No matter what the transmission medium-copper, wireless or fiber optic, the router is electronic, and therefore is copper-based. This means that the connections into and out of the router must be copper. Each router also needs a source of electric power which has to be built with, and wired with, copper.
The Two Telecommunications Revolutions
Analog Communications
During the first half of the 20th century, two systems of electrical communication were developed separately, side-by-side. On the one hand were telephone and telegraph. These were the first systems that allowed people to communicate with each other over long distances in real time. Before that, messages had to be hand-delivered and would take hours or days, depending on the distance. These new systems relied on a network of copper wires, which could transmit messages almost instantaneously. Senders and receivers would be connected through switching centers that would make solid electrical connections between the two. A physical circuit had to be established and dedicated to the communication between the two parties at each end until it was terminated. This technique is called circuit switching.
The second, completely separate, communication means was wireless transmission of radio and television, usually over high-power radio frequency carrier waves.
Digital Communications
The ability to communicate digitally made possible our present-day interconnected world.
The idea for a network of computers was introduced in a 1961 essay by J.C.R. Liklider. "It seems reasonable to envision, for a time 10 or 15 years hence, a thinking center that will incorporate the functions of present-day libraries together with anticipated advances in information storage…. The picture readily enlarges itself into a network of such centers, connected to one another by wide-band communication lines and to individual users by leased-wire services." The ability to establish practical communication networks for computers began in the late 1960s. In 1982, the Internet Protocol Suite (TCP/IP) a standard protocol for digital data transmission was agreed upon. This permitted digital data to be transmitted between different networks and enabled the development of the current world-wide network of networks-the Internet.
The rapid expansion of the Internet is revolutionizing the way information is transmitted. The word "Internet" is actually an acronym that stands for "internetworking." It is based upon a uniformly accepted standard, or protocol, which specifies enough common characteristics of a transmitted message so that it can be sent from one network to another without losing its meaning. This has been made possible by means of a method called packet switching.
Packet Switching
The huge amount of information that is communicated has made the cost of relying on switched circuit technology prohibitively expensive. Packet switching allows any transmission medium to carry a great number of different messages-it doesn't require a fixed connection between two particular nodes as in circuit switching and it allows a single medium to transmit many messages practically at the same time. The key is that the information is coded into digital form. The information (voice, video or data) is broken up into a series of blocks called packets. Each packet contains the IP addresses of the sender and receiver as well as the information being transmitted. The packets can arrive at their destination in any order and then be reassembled to convey their message.
The packets can be sent over any combination of media and can share their physical connections with packets from many different users. The same packet can be transferred from a copper wire to a wireless link to a fiber optical cable and back again to copper. A specialized electronic computer called a router reads the packet code at each node and decides which other router (node) in the network would be best to receive it in order to move it towards its ultimate destination. Each router receives an information packet and then hands it off again to the next router. Not only does this allow many messages to be simultaneously sent over the same connection, but also, the nodes are connected in a mesh structure. This means that the path from end to end is not fixed but can be automatically selected by a router according to factors such as the amount of traffic on a particular path. A router is also the gateway that passes a message from a local area network (LAN) at the source to the outside world and from the outside world into a LAN at the receiving end.
The paths connecting each pair of nodes can be copper wire or wireless RF or optical fiber or any combination of these. But the ultimate connections at each terminal of the communication and at each router must be wire since that is the only means to connect to the electronics within the routers and within the transmitting and receiving computers. Without those copper connections, none of the modern communication systems are possible.
Modern Circuit-switching
Circuit switching is by no means obsolete-its uses, however are dedicated to functions best served by it. It is ideal when data must be transmitted in real time such as for live audio and video, where even the slight time delays that occur with packet switching would be very disconcerting.
Leased Lines
For applications where it is important to send high speed, high quality data, between two fixed points at any chosen time, a service provider will lease a permanent fixed connection to a user. Such arrangements are often used, for example, when a large corporation wishes to have dedicated communication links among all of its branches.
Mobile Phones
Let's take a look at a typical communication path starting at your smart phone. The wireless signal from your cell phone goes to a receiving antenna on a rooftop, or a streetlamp or a cell tower. This antenna is connected by a feeder-coaxial cable into a base station (the hut). From the hut, it travels over a copper (or fiber optic) telephone cable to a switching point-the central office of a telephone company or the head end of a cable TV company. The cross-connections at the phone company are all made with copper cable. "So taking the cell tower example, we quickly go from a wireless world to a wireline world," said Jim Sheridan of Superior Essex Communications LP, Atlanta Georgia.
Distributed Antenna Systems
Distributed antenna systems (DAS) provide high-quality wireless transmission to computers and cell phones in a defined area, which can be a college campus or a city neighborhood. Wireless local distribution can use fiber optic cable that feeds data to a media converter, where it is converted back to high frequency electrical signals at a series of localized antennas, which can be mounted on existing utility poles.
Voice over Internet Protocol
Another rapidly expanding sector is the use of VoIP, whereby ordinary telephones are no longer linked by dedicated lines, but the messages are digitized, converted into packets, and sent over the Internet along with all of the other digital data and then reconverted back to analog electrical signals that can be used by standard analog telephones.
The Future of Copper in the Information Highway
It is quite clear that the information highway (really highways) will continue their incredible expansion as communication and control becomes central to more and more areas of our lives. Although this expansion will call for wireless and fiber optic media, every new link that is created will require copper wires as an indispensable piece of the path. The more connectivity there is, the more there will be the need for copper wire.