Today I tried to find how I can recover a lost password of 3Com Manageable Switch for my further reference, we use 3Com Manageable SuperStack3 Model:3250, you can try this procedure with the other models it might work.
Follow these steps to recover the password:
1. Connect your PC serial port to console port of your device, use Hyper Terminal as a dumb terminal with these communication settings, 8-N-1, Flow Control = Hardware, baud rate = 19200.
2. To force device to go to password recovery mode enter recover for both login and password.
3. Device goes to the recovery mode and it shows counting down for 30 seconds, during this period you should turn of your device and turn it on.
Note: GIVE AT LEAST 15 SECONDS TO THE DEVICE BEFORE TURNING IT ON
4. After starting up, the device asks you for a new admin password.