why must use twisted pair for Ethenet cable? how it work?
552323
By using twisted pairs, the noise on both of the pairs is about the same.  Also, the signal is inverted on one of the two pairs.  That way, when you take the non inverted signal, and subtract the inverted signal from it, you have twice the signal, and none of the noise (since the noise will add positively).  This is the same way that 3-pin microphone cords (XLR) work.
765317
Well, this really borders on electrical engineering. The conversion between a binary stream of unmodified digital data and the transmitted signal occurs through modulation to more fault tolerant and/or less error prone signals. We'll take ethernet as an example. Ethernet uses an inverted version of Manchester encoding. Manchester encoding is used for a multitude of reasons. For example, Manchester encoding is easily synchronised, and is less susceptible to losing the established synchronisation, since there are no long periods between voltage changes on the wire.\n\nManchester encoding features two voltage states per bit. It is the second voltage stage that carries the data. When the bit stream changes states, such as from binary 0 to binary 1, the second voltage stage stays identical to the first, that is, voltage is not changed for the second bit period. When the bit stream keeps the same state from bit to bit, such as a binary 1 followed by another binary 1, the second voltage stage changes to opposite of the first voltage state, signifying the change of state. An example binary string and conversion could be something like\n\nBinary\n\n   1      1      0      1      0      0       1      0\n---------------------------------------------------------------\n lo/hi  lo/hi hi/lo  lo/hi  hi/lo  hi/lo  lo/hi  hi/lo\n\nManchester\n\nThis is how the voltage is put on the wire. As you can see, when two consecutive identical states, such as a 1 followed by a 1 is transmitted, the second stage voltage state is opposite of the following first stage voltage state, while when the bit stream changes states, the second stage voltage state is identical to the following first stage voltage state, and the second stage of that bit is opposite of the first.\n\nEncoding is used in everything from wire transmissions to optical media, such as CDs, where encoding is done on a 1:2 basis. That is, one byte of binary data is encoded to a two byte number sequence to facilitate the varying quality of CD readers and the inevitable wear and tear.\n\nFor radio and cellular use, modulation occurs as well, though this is done by frequency modulation, which is done by the same concept as voltage modulation.\n\nFor more information, you can google (or Wikipedia, there should be articles about these) "Manchester encoding", "Frequency modulation" and "Eight-to-fourteen modulation".
183541
Unshielded twisted pair cable without earth conection
654502
if they both have an ethernet port (this looks like an oversized phone line) then you can connect them together with a special ethernet cable called a cross over cable. this can be obtained at your local computer store, or maybe bestbuy. this is a fast way, it can also be done by a direct firewire link, or an oldfashioned serial link(very slow) or through a network switch/hub/router. this also uses a regular ethernet cable, and any of the hardware mentioned above.
735340
u lucky....it's a scsi standard. better than normal scsi, sometimes referred as ultra-scsi, has less limitations of cable lenght and higher input/output speeds.\n\nlvd (low voltage differential)
332525
If you see ethernet cables, they have two parts. One, the cable itself, second, the RJ45 connectior (the plastic thing at the end of the cable). A Crimper is a device that is used to attach this RJ45 connector to the cable.\n\nHere is a shot of that\nhttp://www.eclipsetools.com/ProductPics/Latest%20.jpegs/300-064.JPG
95622
Easy!! What you need is just a crossed network cable (It's not the same as usual UTF5 cable in just that the TX and RX are swaped. Connect them together (I suppose than your machines already have LAN cards installed). And then follow network configuration wizard in Windows XP (something named like "setup network connection" in control panel).
762824
The answer to this is actually pretty simple - and it applies to the Christmas lights, too.\n\nThe cable (or wire) that the signal passes through is formed of multiple strands of much finer conductor, twisted to form a (relatively) uniform outer surface to which the insulating jacket is bound.\n\nOver time, you'll tend to pull the cord into longer and longer lengths ... with one of two results. Either the twist gets tighter (and the cord appears slightly thinner), or the twist gets looser.\n\nIn either instance, the "memory" of the wire will want to try and return it to its initial configuration (including tightness of twist). Once the stress is off the conductor, back it goes! And probably snarls itself in the occurrence, because you've tried to pack it away in the EXTENDED configuration.\n\nKnotting is another phenomenon entirely. In this case, relative motion of the gathered conductor bundle tends to "slip" one loop against the next. In the extreme, what used to be the outside loop becomes the inside loop ... and you have a potential knot. Unknowingly, you reach in and grab the "new" inside loop and pull ... thereby completing the slippage and you now definitely have a knot!
894482
Bus topology: \n                            All devices are connected to a central cable, called the bus or backbone. Bus networks are relatively inexpensive and easy to install for small networks. Ethernet systems use a bus topology. This topology uses Co-axial Cables.\n\nRing topology : \n                             All devices are connected to one another in the shape of a closed loop, so that each device is connected directly to two other devices, one on either side of it. Ring topologies are relatively expensive and difficult to install, but they offer high bandwidth and can span large distances. Here if and one system become fails, the total network will get collapsed.\n\nStar topology: \n                            All devices are connected to a central hub. Star networks are relatively easy to install and manage, but bottlenecks can occur because all data must pass through the hub. This topology uses UTP CAT5 cables. Normally this type of network is followed in most places.\n\nFor further information along with pic, visit\nhttp://www.webopedia.com/TERM/T/topology.html
79446
U said - \n"Plugging the cable modem straight into a computer may work at times, but it may not."\n\nAll the rtr does is pass on the internet conection to a computer(s).If ur connection from comp itself is not working well,BEFW11S4(which is ok)is not to blame.Cable modems need to be power cycled a lot of times.\nSo i wud suggest that the moment u dont get a connection ,immediatel connect the mdm to comp and call comcast,who wud be bound to do sumthing abt then (as the rtr is not involved now)\n\nOR\nif u feel that the rtr's not working properly,,just call Linksys and get them update the firmware(they'l guide u thru it).Also u can insist on getting it replaced,on the grounds of it not working,but u gotto be adamant and make the call longer than 40 minutes.\nP.S. : yeah befw11s4 is an old rtr,,get a wrt54gsx,if possible
102981
Ok - you really should hire someone to do this - -  but here goes. Buy the ends and a crimper.  Buy an Ethernet hub that has more ports than your number of wires - cheap ones are fine - Linksys is good.  Read this http://www.aptcommunications.com/ncode.htm and follow the 10baseT instructions.  Now try some crimping on a couple of wires that are not in the wall.  Hook two computers with these wires into the hub.  Using the first computer, see if you can 'see' the second one in Network Neighborhood or My Network Places (use Help if you don't know what to do here).  Once you figure out how to wire properly, wire all the ends and plug them all into the hub.  You can do it if you try!
232029
CAT5 is an Ethernet cable standard defined by the Electronic Industries Association and Telecommunications Industry Association (commonly known as EIA/TIA). CAT5 is the 5th generation of twisted pair Ethernet cabling and the most popular of all twisted pair cables in use today. \nCAT5 cable contains four pairs of copper wire. CAT5 supports Fast (100 Mbps) Ethernet and comparable alternatives such as ATM. As with all other types of twisted pair EIA/TIA cabling, CAT5 cable runs are limited to a maximum recommended run rate of 100m (328 feet). \n\nAlthough CAT5 cable usually contains four pairs of copper wire, Fast Ethernet communications only utilize two pairs. A new specification for CAT5 cable, CAT5 enhanced (CAT5e), supports short-run Gigabit Ethernet (1000 Mbps) networking by utilizing all four wire pairs and is backward-compatible with ordinary CAT5. \n\nTwisted pair cable like CAT5 comes in two main varieties, solid and stranded. Solid CAT5 cable supports longer runs and works best in fixed wiring configurations like office buildings. Stranded CAT5 cable, on the other hand, is more pliable and better suited for shorter-distance, movable cabling such as on-the-fly "patch" cabling. \n\nThough newer cable technologies like CAT6 and CAT7 are being developed, CAT5 cable remains the popular choice, because it is both affordable and plenty fast enough for today's LANs
1141592
RJ-45\n\ndon't foget, the 2 wire pairs need to be hooked up in a unique way. Pin 1 & 2 / 3 & 6 need to matched. The others really don't matter.
701526
I found a rather technical but useful page about this.\n\nIt seems without fully reading the page that RS485 uses balanced lines, which means it has two wires for the signal rather than one, the second wire carries an inverted version of the data.\n\nThe reason behind this is that if the cable picks up current from neighbouring cables it will be the same on both wires and will be distinguished from the data because the data always shows up as an opposite signal on the second wire.\n\nThis makes for quite a robust line (in terms of magnetic, electrical and radio interference) which allows you to use the serial link over much longer distances.\n\nThere are other differences but I’ll let you read about them.
163662
Nothing unless you are using a Crosed Ethernet Cable.
356544
Here are the different types of cabling and the maximum distance they can run:  \n\nUse a 10Base5 Thick Coaxial 500 meters\n  \n10BaseT Unshielded Twisted Pair 100 meters\n10Base2 Thin Coaxial 185 meters\n10Base5 Thick Coaxial 500 meters\n10BaseF Fiber Optic 2000 meters\n100BaseT Unshielded Twisted Pair 100 meters\n100BaseTX Unshielded Twisted Pair 220 meters
33964
It is a RS232 port. It used for printers and scanners. It could also be used in the case of embedding technologies. \n\nhttp://www.arcelect.com/rs232.htm