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.
For this particular experiment stress cone is being made of a silicone rubber to provide reliable insulation against different voltage ratings. Silicone rubber is a preferred material for cable accessories due to its excellent mechanical and electrical properties. According to the termination type, there are two methods to manufacture
Fiber optic cables do not carry electricity, which makes them ideal for volatile area's where a spark from a broken copper line could result in explosive consequences. If the fiber optic cable breaks, there is absolutely no risk of electrical shock. Also, the glass fiber will not oxidize like the copper or aluminum wire traditionally used for wiring.
The 1940's and 1950s Cable Television originated in 1948 as a service to households in mountainous or geographically remote areas where reception of over the air television signals was poor. Antennas were erected on mountaintops or other high points, and homes were wired and connected to these towers to receive the broadcast signals.
Token ring was invented by Olof Söderblom in the late 1960s. It was later licensed to IBM, who popularized the use of token ring LANs in the mid 1980s when it released its IBM token ring architecture based on active multi-station access units (MSAUs or MAUs) and the IBM Structured Cabling System. The Institute of Electrical and Electronics Engineers or IEEE (http://www.ieee.org) later standardized a token ring LAN system as IEEE 802.5 (http://www.ieee802.org/5/).
Fast Ethernet Network was developed as an upgrade to traditional Ethernet Networking. Fast Ethernet improved traditional Ethernet by increasing transfer rates 10 times, from 10 Megabit to 100 Megabit speed.
The majority of attenuation in Coax cable comes from resistive losses in the cable's metallic conductors. Temperature also has effects the resistivity of the conducting surface. Resistivity is a "bulk property of material describing how well that material inhibits current flow. This is slightly different from resistance, which is not a physical property. If one considers current flowing through a unit cube of material (say, a solid metal cube that measures 1 meter on each side), resistivity is defined as the voltage measured across the unit cube length (V/m) divided by the current flowing through the unit cube's cross sectional area (I/m2). This results in units of Ohm m2/m or Ohm-m." [University of British Columbia Geophysical Inversion Facility]
Cross-Linked: This term is used for cables that are cross-linked under heat and pressure for better insulation properties. The material is subjected to heat and pressure, and extruded
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.
A "Thin_Client" is a PC which has no hard drive. It depends on another machine for operation. The advantages of a thin client are added security, because obviously the machine it depends on, actually controls the "life blood" of the thin client. This way, whatever security is set up on the host machine, is what rules the thin client's access. A thin client is really just a fancy way to allow a serving machine to host a client. Mainframe and other terminal type systems work on this principal. The client's screen and access to software and file structures is secured at the host. In a business setting, the costs of LAN maintenance is reduced because there is little ability of the thin client user to affect any settings which are critical to the business or workflow operation. In a perfect world all users are "good users", but as reality shows, mistakes are made everyday by curious people using computers. If you are a DP professional, you know this translates into a lot of technical support and help desk calls and operations. The thin client eliminates this. The thin client is also known as a "Network PC"; however, there is much to-do in the computer industry over just what actually constitutes a Network PC, so we use the term "thin-client".
In communication networks, research was performed on Fiber Optics Local Area Networks such as Fastnet, Expressnet, D-Net, U-Net and Token Ring as they are key networks for factory automation. This leads to interest in modelling and testing of High Speed Networks, which is paramount for the successful development of multimedia systems.
Most network and cable programs are transmitted on a series of C-band satellites and some Ku-band satellites. These two types of satellites use different frequencies much as VHF and UHF broadcast TV use different frequencies.
In June, 1997 the IEEE, the body that defined the dominant 802.3 Ethernet standard, released the 802.11 standard for wireless local area networking. IEEE 802.11 standard supports transmission in infrared light and two types of radio transmission within the unlicensed 2.4GHz frequency band: Frequency Hopping Spread Spectrum (FHSS) and Direct Sequence Spread Spectrum (DSSS).
Electrical conduits protect the cables from abrasion, drywall screws, mechanical damage, and exposure to UV rays, chemicals and other external conditions. They provide a means of protecting, supporting, fastening and directing the electrical conductors. However, with so many types of conduits, it can be a challenge determining the one that is deal for a particular application. But installers can get help for major suppliers such as US electrical
they began to disjoin. The cable now in a "v" shape with the weight of