Can I use other fields in Active Directory ?

Yes. You can use the configuration file adolsign.config for that purpose:

field_login = SamAccountName
field_fullname = FullName
field_firstname = FirstName

You can simply add your mappings to the list above. As an example, if you want to use ipPhone value from Active Directory, simply add the line below:

field_ipphone = ipPhone

You can now use field_ipphone in your signature templates.