It’s different in several ways.
First, whenever you register with a Product Serial Number, the Bytescribe software on your computer contacts our registration server to complete the registration. If that contact cannot take place (because of firewall, etc.), then the software cannot register.
With the Dongle, the registration is contained on the Dongle itself. There is no need for the software to communicate with our registration server. So you can register your software even if disconnected from the Internet, or without making any changes to your firewall.
Second, a Product Serial Number is limited to 3 consecutive registrations. A Dongle does not have a limit for consecutive registrations. (Please note: all Bytescribe software is limited to one, single concurrent registration.)