inde, I didn't get your first question about the conf register. If you mean how many bits is the configuration register, its 16 bits and its value is always talked about in hexadecimal (thats why to 0x) Check
www.routergod.com
they have a cool tutorial on the configuration register settings and what each bit does. (alternatively there's a post somewhere here called 'So you think you know your routers' which has some stuff on it.
Question two:
The console port (referred to as con0) provides local access management functions.
Question three :
You start in rommon mode by holding down break during the boot sequence. Then you set the configuration register to 0x2142 (or anything with 4 as the third value from the left) setting that tells the router to ignore whatever configuration is in NVRAM (the startup-config).
Then you reload, and the router starts without any config loaded, so you bypass the password. Then you copy the startup-config into running-config (RAM) so you can change the password. Change the password and save the new password by copying running-config to startup-config (basically overwrite the old password with the new one you've set).
The basic reason you're doing these steps is
1. Tell the router to ignore the current config
2. Boot without a config, bypassing password protection
3. Load your normal startup config with the forgotten password by copying it into RAM (running-config) from NVRAM (startup-config).
4. Change the password in the RAM config (running-conf)
5. Save your changes by copying RAM config (running-conf) to the NVRAM (startup-conf).
5. When your router reloads it requires the new password for access.
Hope that helps,
