ENERCALC's Internet Activation system is a very convenient means by which to obtain "activation", i.e. "permission" to run one or more installations of the Structural Engineering Library (SEL) on your computer(s).
It provides a way for your RetainPro installation to communicate with the ENERCALC Internet Activation server and "request" an activation. As long as you have an available "seat" in your "pool" of licenses, the Internet Activation server will grant permission for your program to run. If the server finds that you have already used all of your available "seats", then it will provide an informative text box indicating this, and it will give you the option to view a list of currently activated users.
There are a couple important features to note:
1. The Internet Activation system offers the option to "Indefinitely" activate a computer. This can be a very convenient option if you only run the program on a single computer. This option will activate the computer indefinitely (until you intentionally deactivate it). This can be useful in situations where you might take a laptop to a remote location where there is no Internet access. It can also be helpful in situations where Internet service is somewhat unreliable, because it eliminates the need for the program to request permission to run each time it is launched.
2. The Internet Activation system also offers a convenient option to automatically activate a computer when the program is launched, and automatically deactivate the computer when the program is closed. This can be a convenient and very efficient way to share "seats" in situations where there are more potential users than "seats" in your "pool". By allowing the system to automatically request an activation when you launch and return the activation when you exit, it allows you to minimize the number of "seats" you must purchase and support in order to keep your staff fully functional. (When used in this way, the Internet Activation system does ping the ENERCALC Internet Activation system each time the program is launched, so it does depend upon your having a reliable Internet connection.)