back to back t1

[RadioX]

I am connecting a T1 CSU/DSU to another t1 CSU/DSU directly (i.e. no patch pannel, jacks or anything like that) Do I ned to have a crossover cable for them and if so how are the pinouts. I thought they were as follows

1 5
2 4
3 3
4 2
5 1
6 6
7 7
8 8

If I am wrong then somone please correct me or tell me how this is done.

Thanks
Ron

 

[wybnormal]

1 to 5
2 to 4
4 to 2
5 to 1

two pair..

MikeS Find me at

http://www.packetattack.com

"Diplomacy; the art of saying 'nice doggie' till you can find a rock" Wynn Catlin

 

[RadioX]

Thats what I have done I am getting a green and orange light on my 3620 which has a vwic2mft-t1 card in it and no lghts on my 7206. Any ideas.

Thanks
Ron

 

[wybnormal]

try this.. make a loopback connector... and see if the link comes up..

RJ-45
1-5
2-4

Cut off the rest of the wiring or just make it with two wires..

Jack the plug in and see if the link comes up. If it does go to the next link.. if it does.. check the configs on both CSUs to make sure the speeds, bit counts, channel counts and encoding is the same.

A link about this is:

http://www.cisco.com/warp/public/471/hard_loopback.html#subfirsttwo

MikeS

Find me at

http://www.packetattack.com

"Diplomacy; the art of saying 'nice doggie' till you can find a rock" Wynn Catlin

 

[RadioX]

why does cisco say to twist 1 and 4 together and 2 and 5 together if the configuration is 1 and 5 (and) 2 and 4.

Is this just me being ignorant or am I midding something here?

Thanks
Ron

 

[jeter]

pins 1245 is how a the transmit and recieve are pinned out on the jack Rj-45 RJ-48 Jeter@LasVegas.com
J.Fisher CCNA

 

[wybnormal]

Jeter is right.. forgive me if I get my own wires cross as I'm writing these answers while watching CNN.

One pair is a TX and one pair is a RX.. and within each pair there is a + and a - wire.. not - voltage per say.. these are differential signals so think of of it this way... when the + signal goes high, the - signal will mirror it by going low. The point is to help cancel out noise.

so you need to feed the TX to RX and RX back to TX.

MikeS Find me at

http://www.packetattack.com

"Diplomacy; the art of saying 'nice doggie' till you can find a rock" Wynn Catlin