This happens to use when using Dell Laptops. If we plug in the console port and then launch Hyperterminal it causes our Cat6500's to go into RMON. Very bad on a production switch. This does not happen with IBM Laptops that we also use. Anyway, if you connect your cable to your laptop, launch hyperterminal, activate your COM serial connection, then as the last step plug in the console cable to the switch it shouldn't crash the switch. Hope this works for you!
