Use a straight through serial cable, (2,3,5 connected to each other on both ends), 9 pin, female on both ends. Null modem cables are used for the Contivity, Accelar and some Passport devices, but for some reason the edge switches remained straight through. Radio Shack has them for under $10. 9600-8-N-1, flow control off. Press Control-Y, and you should see the login menu.
If you don't know the password, there isn't anyway to recover the password (that I'm aware of, someone please correct me if theres a better way) except to stack the unit with another 450/BPS/460, etc with a known password, then do a factory reset on the stack. The unit you are stacking it with should have the same software rev as the system you are trying to recover the password from. You might be able factory reset the switch through Device Manager using SNMP, provided you know the SNMP strings and IP address. IP address might be hard to get without a serial cable, but it is doable with sniffer utilites.