I'm using the normal blue RJ45 to DB9 cable plugged into my Cisco Catalyst 3500 series XL switch. That cable is connected to a serial-to-usb adapter that I got from Monoprice, and that is plugged into my computer (running Windows 7).
When I go into the device manager, I see that it uses COM5, so I'm trying to connect to that with putty. However, when I click "open" it just opens a black screen in putty. When I hit enter, nothing happens. I've tried looking around, but I can't figure out how to get into the switch. So far, I've tried updating the driver. Windows says it's update to date. I've tried matching the settings I see in the device manager to the settings in putty:
Bits per second: 9600
Data bits: 8
Stop bits: 1
Flow control: None
I've also tried changing some of those settings to see if anything would happen, but it's the same result every time. I've changed them back to as they are above.
It seems that my computer recognizes the device and the connection because of what it shows in the device manager, but it just seems to be refusing to communicate. If I try to make the connection in putty, and then unplug the cable from my computer I get an error message: "Error reading from serial device". If I unplug from the switch, or unplug the adapter, I get no error. I've also tried using a second switch (same model), and I get the same results.