[cisco-voip] T1 xover or straight through?

[Dane]

First I wanted to say thanks for the replies and information.

Second, well I got it sorted out finally.  I took down one of the
PRI's after hours from the IAD and connected it to the 3845 with a
straight through cable just to test.  It did not come up which is what
I think I and everyone who responded on this list would have expected.
 I connected the IAD to the 3845 with a T1 crossover just as I have
the IAD connected to my CMM-6T1s and it came up.

Now the kicker is that this same 3845 T1/PRI port connected to the
AT&T demarc requires a straight through cable.

I have to be honest and admit that this confuses me.  Of course its
4am and I have been busting my ass since 6am so I am not able to
mentally sort this out.  Have to give it some thought when I have my
wits how the 3845 port takes either a T1 crossover or a straight
through depending on the other side apparently.

Anyway, I thought it was interesting to note and share.

Thanks again for the help.





On Mon, Jun 1, 2009 at 12:31 PM, Go0se<me at go0se.com> wrote:
> As a general rule a T1 crossover cable is always required between PBXs no
> matter how you interconnect them. I'm not aware of a T1 controller that will
> auto-mdix. You can build your own T1 crossover - cross pins 1&2 to pins 4&5.
> (1 to 4 and 2 to 5)
>
> -Go0se
> http://atc.go0se.com
>
> -----Original Message-----
> From: cisco-voip-bounces at puck.nether.net
> [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Dane
> Sent: Monday, June 01, 2009 11:28 AM
> To: cisco-voip at puck.nether.net
> Subject: [cisco-voip] T1 xover or straight through?
>
> Anyone know if you need a straight through or t1 crossover to go from
> an IAD to a 3845 with a PRI port?  We have some IAD's that terminate
> with CMM's and those use t1 crossovers.  Not sure about the 3845
> ports.
>
> Connecting to AT&T circuits to the 3845's required straight through.
> Wish I had one to test.
>
> Just wondering if anyone might know, wondering if the 3845s can handle
> either / or, and if the requirement comes from the demarc side (either
> AT&T or IAD's).
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