Here you will find the settings that you will need to set TELNET to so that you can connect to the HP procurve switch using the console Cable. These-settings work fine on the e series witch and the a-series switch.
8 data bits
1 stop bit
No Flow control
Once you have connected your console cable to the procurve switch and set telnet as the settings above. Run telnet then double tap space at the prompt. Then will get prompted for authentication. Once logged in you can then configure the procurve switch.