Twisted pair and Coaxial cables?

Question

I need to know why we require two conductors in a twisted pair cable...
If one is for transmission and other for reception, how come a single copper wire in coaxial cable does both the operations...?

Answer 1

Maybe this will help.
http://www.techfest.com/networking/lan/ethernet5.htm

Answer 2

Simple really. It's all about induced electrical noise on the "wire". Networking cables run in ceilings and places were they can be exposed to all kinds of electrical noise, motors in fans, power lines etc...

Twisted pair has two wires to Tx and two for Rx, being Tx+/Tx- and Rx+/RX-. The + wires have a positive going signal from ground, the - have the same signal only negative going. When noise in introduced it effects both the positive and negative signals the same. When the signal is received it's put through a differential amplifier - so the only that comes out is the difference, which is the original signal. The noise is stripped off.

You don't have this problem with coax because it's shielded and grounded.

Answer 3

Can you be more specific? Are you talking about using DSL, compared to Cable? because, as the other gentleman put it, there's actually several wires in the cable known as "twisted pair" it should be called, Twisted Pairs! But seriously he never answered you question, and neither can I, unless I know what you're talking about.

DSL used to lines from the unused phonelines that we all have in our homes (they have four wires, but only use two for the phone), while Cable uses a Coaxial Cable that has more current thant the 9volts of a standard phone line... The lines on the phone are also known as half duplex, (send data one way, recieve the same... one way), so two are used... while a coaxial has more power, it's also thicker, and is full duplex (sends data both ways).

I hope this helps a bit...it's a limited answer, to a limited question. give me more, and I can give you more.
Sincerely;
Marcos

Answer 4

The twisted pair is actually a Cat5 cable which is more than just 2 wires, it has 8 if I'm not mistaken. The way they are twisted actually helps prevent signal interference since the cable doesn't have much inulation and is therefore more flexible. A Coaxial cable has several layers of insulation or "shielding" to prevent that exact same signal loss. but it comes at the cost of flexibility. Not to mention Cat5 is a far more common setup and when using it you can connect to any network you happen to need.

Answer 5

1. It's cheaper 2. It works in a true star configuration. (Coax was a pass-trough ring or bus. Also, if there was a break in the cable, all hosts went off line.) 3. It allows the use of switched systems. More efficient. 4. It's faster. Coax capped out at 10 Mbps while twisted pair supports up to a full gigabit currently.

Answer 6

Simply in coaxial there is an two channel frequency or more but in twisted pair have on channel but u can also use two or more channel on twisted pair by frequency modulation
its nothing simple operation

Answer 7

Look, point is in purpose of cables. Coax is especially constructed for HF (high frequency) signals but twisted pair cable is constructed for general purpose. Every cable must contain minimum two wires and one of them is for signal flow and second is ground. In the coax wire for signal flow is in the middle and around is plait as the ground wich in same time working as "cage" for HF signals. Twisted pair cables you can not use for HF signals because loss of high frequency in them is enormous. Veradisca & Best Regards, Neven.

Answer 8

Actually, you misunderstand why we use UTP (twisted pairs.)

Coax is very heavy, expensive and is designed for long runs between devices.

Cat 5 is cheap, very lightweight, easy to pull around bends & because of the twists, doesn't need the shielding. It is designed for runs around 300 ft or less, and other protocols can use cat5 that cannot use coax.