# Cross Over Cable & Straight Through Cable



## State_Trooper (Mar 20, 2005)

Hi
Well, a topic not exactly related to Laptops, still it concerns my IBM thinkpad. So i would like to post it around.
1. I need to share my dial up internet conncetion between laptop and desktop, so i brought this cable as sold to me saying its a LAN cable, and tried to configure home network, while using WINXP on laptop and WINME on dektop. There was absolutely no respose between the two computers. No LED's flashing nothing.
2. Now, as far as i know, a cross over cable is used to connect two computers directly okay. But what about a straight through cable? We do connect computers with it too. Some say, straight through is for connection host and client, so why cant i have my dekstop as host and laptop as client. Is this cable selection related to hardware or the way you configure your computer? Please explain me both the ways to setup between dektop and laptop.
3. Now a purely network related query, what is 10/100 mbps? In simple words i understand one transmits data for 10mbps and other over 100mbps. Still whats is the basic difference, is this again hardware or software. A Ca5 cable or something. What kind of cable do i need? What is the difference between these cables.

I would be greatful if you can explain me, though all i need is just a simple internet sharing connection between my desktop and laptop.

regards
Ayush Singh


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## Volt-Schwibe (Jan 12, 2003)

it has to do with the wiring, a straight through cable will connect 2 network cards "ear to ear" and "mouth to mouth" so they obviously won't be able to talk.

this is because a network cable contains 2 actual sets of 2 wire transmission lines, and a network card is talking on "A" and listening on "B". if two network cards are talking on "A" and listening on "B" then neither will hear the other, and they will scream into the phone and get no response.

but, a router or hub, or switching hub talks on "B" and listens on "A" so it can easily hear all the network cards talking on "A" and the network cards can easily hear the router talking on "B"

in effect, a crossover simply "turns the handset around" so that they are "mouth to ear" like they should be.


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## State_Trooper (Mar 20, 2005)

*IBM 2681 with Realtech 10/100 MBPS*

Hi
Well that was a good illustration. ANd i got it right. My dekstops lan adpater says, 10/100 and laptops says 100MBS. I m using a Category 5e cable. But when i connect the cable to desktop and laptop, no lights turn on. Am i using a wrong cable? What else could be a problem? Why aint any lights getting on. Shall i try a direct cable? PLease help me out.
Laptop is with INtel chipset 100MBPS lan card.(What it says)

regards
Ayush


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## Lectraplayer (Aug 24, 2002)

Try a crossover cable and see what happens. Also, be sure it's really up in there, they tend to work loose for some reason. :dead:


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## State_Trooper (Mar 20, 2005)

Well thats what i am using, a cross over cable. And it doesnt shows any link at all. Has anyone ever used a straight through cable in between a laptop and desktop?. THe cable's pins are okay and the laptop end gets hooked up properly, but the other end to the card in desktop is loose, so i tried holding it up with hand, still no luck. THe card is not a new one, i have borowed it. But the card dtectes itself very well and no IRQ conflicts at all. Can the card be physically damaged and still showing its all ok with the drivers?
Its so confusing

regards
Ayush


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## johnwill (Sep 26, 2002)

Yes, a damaged connector won't show up internally, only when you want to use the network.


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## Volt-Schwibe (Jan 12, 2003)

State_Trooper said:


> Well thats what i am using, a cross over cable.



not to badger you about it, but does it say on it that it is a "crossover" or "x-over"?

i'm just wondering if it for sure is x-over. for what it's worth, a straight cable won't break anything, but it won't work.


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## State_Trooper (Mar 20, 2005)

Well thanks a lot for your intrest and advice guys.
1st to check the connector i got hol dof the card and looked over each and every soldering, cant find a single broken soldering, still i used a multi meter to check the pins and bingo they were all well.
2nd the cable is cross over as i have the pin outs with me and i checked the pins with multimeter, all in the right place.
Most importantly, i looked over the forum in Network section and found a guy with same adapters and same problem. He solved it by using a hub, which is so very common. But i wanna know why it aint wokrin? We all know for every action theres a reaction, so there must be something to solve it.

I even edited the Intel (Laptops) lan speed setting tried 10mbps/half duplex and ended in vain. Got the latest realtech drivers and updates, still nothing.
I know one can accesse using different OS, but still any changes in the settings in required for it? 

regards
Ayush


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## johnwill (Sep 26, 2002)

I have seen the problem of two machines having an electrical incompatibility, and a hub or switch solves the problem. I don't know why I didn't think of it in this case. That's yet another thing you might consider, even though we didn't think of it. :smile:


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