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T1 Crossover Cable

Created by: admin,Last modification on Fri 22 of Dec, 2006 [04:23 UTC] by NetForces
See also: crossover T1 cable

Two devices with PRI interfaces can be connected together with a PRI crossover or null-modem cable.


It should be emphasized that while a common ethernet patch cord can by used just fine for a PRI patch cord (they are both 4 pair RJ45 straight thru's), the different signal assigments suddenly matter when building a crossover. Therefore the "Ethernet Crossover Cable" can NOT (:eek:) be used as a substitute for a "PRI crossover".

What's more, the PRI crossover cable seems to be a pretty rare item. Most places you ask for it will hear the words "cross over cable" and ask a few times if you want an ethernet x-o. Just say no! (:frown:) You will probably just end up rolling your own. (:wink:)

I avoid crimping my own cables and being left doubting their integrity, so I use regular patch cords but built a F/F cross over box using a 2 port RJ45 housing. IMHO, jacks in a box (:rolleyes:) are easier to handle, see, label, verify, correct and change. It also allows for easier cable swapping for diagnosis and for length and color changes.
Image

For those using a 586A wall type box, here is a picture of a working one wired for a T1 crossover:
Image


Comments

Comments Filter
222

333Are the pins right? 12 56? Really?

by ppuskari, Friday 17 of August, 2007 [03:54:25 UTC]
I've built a few cables and back to backs over the last year. What am I missing in your ethernet jack picture? Shouldn't a T1 cross cabling be pins 1-2 to 4-5 and crossed? Or is that a ramification I'm not allowing for in the pinouts of your connection box... I see 1-2 5-6 and crossed.. Curious.
222

333

by marduk, Saturday 24 of March, 2007 [18:40:11 UTC]
Can you tell me how should I check if two T1/E1 ports are looped with a crossover cable on Cisco? What should ISDN status and inteface status look like?
222

333Like the box... how do you make it?

by chumbella, Thursday 10 of November, 2005 [13:42:20 UTC]
I would like to make three or four of these crossover boxes you described - could you provide a bit more detail on how to pin them out, where to locate the box used, etc? I would love to have these for my router lab environment - thanks in advance for your help!
222

333Channel banks hooked to Digium T1

by Randomandy, Saturday 09 of April, 2005 [10:32:15 UTC]
(:eek:) For example, if you are appending a channel bank onto Asterisk by way of T1, both the Digium TE100P card and a typical channel bank think of themselves as customer premise equipment, thus requiring a crossover to connect them functionally.