To configure the stack of m6220 switches, I use the db9-usb cable which is provided with the switches. My new laptop doesn't have a serial connection anymore.
To use a usb-to-serial converter and then the dell db9-to-usb cable does not seem logical. Is is possible to use an usb cable from the laptop to the console port and use telnet/hyperterminal?

You could also telnet into the CMC, and then use the command "connect switch-x" where x is the ID of the switch you want to connect to.