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Joined: Sep 2006
Posts: 8
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Joined: Sep 2006
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Can anybody tell me if it is possible to reverse Tip and Rings on a T-1 cross over cable and have it still work. Sounds strange, but I am being told it works. Cable in questions is wired: 5-1 4-2 1-5 2-4 I know this isn't standard, but am wondering if it would really work.
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Joined: Jan 2005
Posts: 15,394 Likes: 17
Moderator-Vertical, Vodavi, 1A2, Outside Wire
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Moderator-Vertical, Vodavi, 1A2, Outside Wire
Joined: Jan 2005
Posts: 15,394 Likes: 17 |
Tip and ring (pair polarity) is not significant per-pair, but the placement of the pair is. Your cable illustrated is a true crossover cable. The only other configuration that will work for a T1 is:
1-1 1-2 4-4 5-5
Anything else can't be used on a properly-wired RJ48X jack.
Ed Vaughn, MBSWWYPBX
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Joined: Sep 2006
Posts: 8
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Joined: Sep 2006
Posts: 8 |
Ed,
I thought the correct wiring would be: 1-4 2-5 4-1 5-2 If you look at Cisco or Adtran's websites the above is what they recommend. So, now I'm really confused based on your reply above.
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Joined: Jul 2003
Posts: 6,768
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I always use a standard patch cable (straight through)with no problems.
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Joined: Mar 2006
Posts: 575
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You can't always use a straight through cable, when you're hooking up equipment which expects to be the user end as opposed to a network end. For example, from the smartjack to my adtran, is straight. From the adtran to my PBX is crossed-over when I punched to the block. To hook up other equipment, I made an adapter out of two RJ45 jacks back-to-back, with the wires crossed. Then I use two factory straight cables to make the final connection.
Rob Cashman Customer Support Engineer
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Joined: Aug 2006
Posts: 89
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Joined: Aug 2006
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We have always used a true "Cross-Over" cable when going from an Adtran to a router or switch and have never had any problems. If the router is located in a different area than the Adtran, we run a Cat-5 cable, and terminate one end 568-B and the other end 568-A. This creates a "Crossover" connection between the Adtran and the router, and a standard straight thru patch cord can be used on both ends to patch in to the equipment.
Kirk Herron A mistake on your part does not constitute an emergency on my part. CCSG, Inc. www.ccsgweb.com
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Joined: Jul 2001
Posts: 3,347 Likes: 10
Moderator-Avaya-Lucent, Antique Tele
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Moderator-Avaya-Lucent, Antique Tele
Joined: Jul 2001
Posts: 3,347 Likes: 10 |
568-A and 568-B will give you an ETHERNET cross over.
For a T-1 cross over, it is 1&2 swapped with 4&5.
If you're going to use 568-B jacks, swap the BLUE and ORANGE at one end.
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Joined: Mar 2001
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To add my for instance to Touch Tone Tommy's advice, when we specify a PRI to a Nortel from an SDSL circuit, it is a standard straight through from the smart jack to the router and a standard straight through from the router to the server.
THEN from the server to the Nortel DTi card it is a Telco Crossover, straight through on one end and 1 & 2 in place of 4 & 5 on the other end. You are only using two pairs with pins 1, 2, 4 and 5.
THE Bracha, old blond specialist in Rube Goldberg solutions.
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