Introduction
Coaxial cable: is an electrical cable consisting of a round conducting wire, surrounded by an insulating spacer, surrounded by a cylindrical conducting sheath, usually surrounded by a final insulating layer. It is used as a high-frequency transmission line to carry a high-frequency or broadband signal. Sometimes DC power (called bias) is added to the signal to supply the equipment at the other end, as in direct broadcast satellite receivers. Because the electromagnetic field carrying the signal exists (ideally) only in the space between the inner and outer conductors, it cannot interfere with or suffer interference from external electromagnetic fields.
Coaxial cables may be rigid or flexible. Rigid types have a solid sheath, while flexible types have a braided sheath, both usually of thin copper wire. The inner insulator, also called the dielectric, has a significant effect on the cable's properties, such as its characteristic impedance and its attenuation. The dielectric may be solid or perforated with air spaces. Connections to the ends of coaxial cables are usually made with RF connectors.
Radio-grade flexible coaxial cable.
A: outer plastic sheath
B: copper screen
C: inner dielectric insulator
D: copper core
There are two types of coaxial cables:
1. Thinnet
2. Thicknet
Thinnet
Also known as "Thin Ethernet" or Thinnet, 10BASE-2 is an IEEE standard for baseband Ethernet at 10MBps over thick coaxial cable. 10Base2 has a maximum distance of 185 meters. Thin Ethernet is five millimeters in diameter and used to connect machines up to 1,000 feet apart.
Thinnet (thin Ethernet) is an incarnation of the Ethernet standard in which coaxial cables are used in a LAN (local-area network) configuration to connect computers together. A Thinnet setup is capable of transmitting data at a rate of 10Mbps (megabits per second). It is also cheaper and easier to install than Thicknet.
The first variation on the original variety of Ethernet was simply to use a thinner coaxial cable and relax the constraints on how and where transceivers can connect. 10BASE-2 does this with coaxial cable that looks just like the cable used for receiving cable television or hooking up a television set to an antenna. The only difference in the cable itself is the impedance rating. A television cable is rated at 75 ohms and a 10BASE-2 cable is rated at 50 ohms. In a pinch, a small length of one can be substituted for the other.
The connectors used in 10BASE-2 are called BNC connectors for Berkeley Nucleonics Co.: they were originally used in nuclear physics.
In 1950, the use of a single-channel "strip-amp" amplifier permitted the extension of cable systems to homes located even farther from the receiving antenna. In 1957, Jerrold Electronics Corp. began marketing an All-Channel Broadband amplifier for channels 2-13 and the ABC (All-Band-Cascader) covering channels 1-13 plus FM. "The primary challenges and issues in the '40s and '50s were everywhere. There were no satellites, no microwaves and we relied on off-air reception. So, our concerns were antennas, and signal-to-noise ratios. So we're out there trying to figure out co-channel problems, and with limited resources," said Bill Karnes, one of the first engineers at Jerrold, and the Society of Cable Television Engineers' (SCTE) first full-time president. Cable T.V. was a big improvement among antennas that could be affected by weather and could produce bad signals and as the 1950s came to an end, cable T.V. left its mark on society.
“The Spanning Tree Protocol (STP) is an older network protocol that ensures a loop-free topology for any bridged Ethernet local area network. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them.”
For the west subnet, one ethernet_server and one ethernet4_slip8_gtwy router are connected with a bidirectional 100 BaseT link. The attributes of the server are shown in the picture
2-frequency:- as the frequwncy of the applied voltage increase, the dielectric strength will reduce. 3-the exisistence of humidity lead to decrese dielectric strength. 4-also the presence of surface defect like crack ,pore, decresing the dielectric strength.[53]
Like a lot inventions in the past two centuries, modern fibre optic cable was created for military uses. The manager for Copper Cable and Wire at the US Army Signal Corps was getting more displeased with the amount of signal loss that was due to copper cable.
The Unistep IRP Elexol EtherIO 24 Module is a network board that is integrated with features that allow multiple devices over the same network to communicate. This microcontroller was designed to be implemented as an addition to a larger network system; the multiple features and capabilities allow for various industrial and home applications. Ethernet is very common and used in most networks, which makes the IRP a great candidate for networking problems both at home and in the work field.
The terminals are fitted into the connector housings as shown in figure 1.2. Housing is a connector's casing which is made of molded plastics such as polyamide, polycarbonate, polyethylene etc. The main function of housing is to hold the terminals and protect them from electrical shorting, electrical interference, dust, dirt, and moisture.
Sending data through the internet efficiently has always posed many problems. The two major technologies used, Ethernet and Asynchronous Transfer Mode (ATM), have done an admirable job of porting data, voice and video from one point to another. However, they both fall short in differing areas; neither has been able to present the "complete" package to become the single, dominant player in the internet market. They both have dominant areas they cover. Ethernet has dominated the LAN side, while ATM covers the WAN (backbone). This paper will compare the two technologies and determine which has a hand-up in the data trafficking world.
This is know as resistivity. The factors I can investigate are : Ÿ Temperature Ÿ Length Ÿ Cross-sectional area/width Ÿ Material (resistivity) The factor I shall investigate is the length of a wire. Background Knowledge Resistance is when electrons travelling through the wire are impeded by the atoms within the wire. Since the electrons are charge carriers when they collide with the atoms in the wire less pass through.
By 1950, 70 cable systems served 14,000 subscribers nationwide. In late 1950s, when cable operators began to take advantage of their ability to pick up broadcast signals from hundreds of miles access to these "distant signals" changed the focus of cable's role from one of transmitting local broadcast signals to one of providing new programming choices.
It just doesn't get much simpler than the physical bus topology when it comes to connecting nodes on a Local Area Network (LAN). The most common implementation of a linear bus topology is IEEE 802.3 Ethernet. All devices in a bus topology are connected to a single cable called the bus, backbone, or ether. The transmission medium has a physical beginning and an end. All connections must be terminated with a resistor to keep data transmissions from being mistaken as network traffic. The terminating resistor must match the impedance of the cable.
Local Area Networks also called LANs have been a major player in industrialization of computers. In the past 20 or so years the worlds industry has be invaded with new computer technology. It has made such an impact on the way we do business that it has become essential with an ever-growing need for improvement. LANs give an employer the ability to share information between computers with a simple relatively inexpensive system of network cards and software. It also lets the user or users share hardware such as Printers and scanners. The speed of access between the computers is lighting fast because the data has a short distance to cover. In most cases a LAN only occupies one or a group of buildings located next to each other. For larger area need there are several other types of networks such as the Internet.
they began to disjoin. The cable now in a "v" shape with the weight of