Bent Pins by design?

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Nov 18th, 2008
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We have 7 Catalyst 3750 Switches. 5 are 3750 PoE-48's and 2 are 3750G. We noticed that the ports on the 3750G looked pretty standard, but all the ports on 4 of the 5 PoE-48's have a pair of pins bent upward.

We've sat down and hypothesized their reason. We wondered if they were the pins used for PoE and there was some reason to connect them first, before the other pins.

We wonder about the 5th PoE 48, however. Its ports look identical to the 3750G's. If there is a reason to have the bent pins, are these the wrong ports installed in this PoE 48? And if this switch is fine and these pins do not need to be bent, why are they bent in the other 4?

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mchin345 Tue, 11/25/2008 - 14:08
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I'm not so sure those pins are suppose to be bent. Have you called TAC on this?

karnaad47 Wed, 11/26/2008 - 05:49
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I posted this question as a curiosity. Though I use them, I'm not actually the person in charge of said switches, and the person who is is not concerned enough to make a call about it. The switches with the bent pins are installed and working properly.

It appears to be on purpose. As I said, the same two pins on all ports are bent. Furthermore, they are all bent up at the same angle in the same, uniform, manner. (This is not the kind of bending that comes from damage) I've seen connectors have pins like this before, but I've never been sure of the purpose.

karnaad47 Wed, 11/26/2008 - 05:57
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It just reread my post and it occured to me that I should clarify... by "bent upward" I'm not talking about the pin sticking out and pointing up, it is bend like an elbow, with the elbow part sticking up from the plane of the other pins.

rduke Wed, 11/26/2008 - 06:33
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I don't have any 3750s where I work now. I did have some where I used to work, and I think I know what you are talking about. The pins don't line up evenly. The thing is, you are looking at the connector when the rj-45 is not plugged into the port. When a cable is plugged in, they are probably perfectly aligned. It is hard to say why it was done that way, but not really worth worrying about. It is not likely to be a PoE issue since power can be applied to any of the pins depending on the device attached. Some devices can run on 1+2,3+6; others on 4+5,7+8. Also don't forget PoE can be reversed if a crossover is used. I have seen a lot of connector problems, but never had any trouble with those.

I did have a nasty issue with the G version of 3750 when I was doing network upgrades. It turns out that old 10 mb hubs would not work reliably in the 3750 10/100/1000 ports. I had to install a switch with 10/100 ports between them until I could get the hubs replaced. It took me a while to figure that one out. They were old baystack hubs - old junk.



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