Roll-over cable VS Cross-over

ztahie

HI.
hope some1 can explain this in basic words....
what are the diffrences between those cables and when I need to connect each one ?

EdTheLad

Standard cable is a straight through cable meaning from left to right the pins go from 1-1,2-2,3-3,...8-8 i.e. all the connections are straight.

Crossover cable is the same as the straight through cable except the transmit
receive pairs are crossed.The transmit receive pins are 1,3,2,6
so 1-3,2-6, and the rest straight.

Rollover cable,basically means the straight cable on one site has been reversed. So pins are 1-8,2-7,3-6,4-5

Staight is used between pc and hub,pc and switch,router and switch.
Cross is used between router and router,pc and router, pc and pc,hub and hub,switch and switch.
Rollover is used for the cisco console lead,not really used all that much.

BubbaJ

ed_the_lad wrote:

Crossover cable is the same as the straight through cable except the transmit receive pairs are crossed.The transmit receive pins are 1,3,2,6 so 1-3,2-6, and the rest straight.

That's not a complete crossover cable, and it won't work with several types of networks including 1000BaseT ethernet.

In a complete crossover cable, it is:

1 <-> 3
2 <-> 6
3 <-> 1
4 <-> 7
5 <-> 8
6 <-> 2
7 <-> 4
8 <-> 5

rotellam1

Every crossover I have ever used was: 1-3 2-6 3-1 4-4 5-5 6-1 7-7 8-8. Also, how do you break to the next line when posting here?

theodoxa

BubbaJ wrote: »

That's not a complete crossover cable, and it won't work with several types of networks including 1000BaseT ethernet.

In a complete crossover cable, it is:

1 <-> 3
2 <-> 6
3 <-> 1
4 <-> 7
5 <-> 8
6 <-> 2
7 <-> 4
8 <-> 5

My understanding is that it should work for 10/100 Mbps, but the extra pairs are required for 1000 Mbps (1 Gbps). Interestingly, it worked on a couple of my switches (@ 1 Gbps) with only two of the pairs cross, but I suspect this was because the switches support Auto-MDIX [which most older equipment doesn't.]

theodoxa

I don't know why the CCNA texts use pin numbers so much. I have always used wire colors as does everyone I know who rolls their own cables.

1 (Orange-White) <-> 3 (Green-White)
2 (Orange) <-> 6 (Green)
3 (Green-White) <-> 1 (Orange-White)
4 (Blue) <-> 7 (Brown-White)
5 (Blue-White) <-> 8 (Brown)
6 (Green) <-> 2 (Orange)
7 (Brown-White) <-> 4 (Blue)
8 (Brown) <-> 5 (Blue-White)

One thing to note is that while you flip stripes for stripes (Orange White <-> Green White) and solids for solids (Orange <-> Green) on the 10/100, for the extra 1000 Mbps pairs, the stripes and solids flip also (Brown <-> Blue White, Blue <-> Brown White), serving to make it slightly more confusing than need be.