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I have a new Cisco 3750X switch and I want to connect to it via console.

Only.... this switch does not have a DB9 connector on it, its Serial port is RJ45. I have a USB to RJ45 cable, and am on Windows 7, but cannot seem to get Putty or other terminal clients to work.

How can I do a console connection to this switch? Thanks!

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Many network devices use the Yost RJ45 pinout for RS-232 console communications. Cisco is probably the best known, but certainly not the only. The switch should have come with a DB9 to RJ45 blue cable. You can just pickup any USB-DB9 Serial adapter (though I highly recommend getting one with a Prolific PL2303HX Rev D Chipset, as they "just work" and are compatible with a wide array of OSes).

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Once you get your Serial-to-USB adapter to work. You still require the proper serial line settings for the majority of Cisco switches.

FYI, they are...
9600 baud
8 data bits
1 stop bits
parity - none
flow-control xon/xoff or none.

Lastly - a lot of the newer Cisco equipment does come with mini-USB console port which which prevents you from having to purchase a serial-to-usb adapter. However you need to have the Cisco console port driver downloaded on your computer. Here's a quick guide with some useful info.

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