License activation in ZKTeco's ZKAcces3.5 software

ZKTeco's ZkAccess3.5 software requires one license, free of charge for up to 25 doors. To download this free license, we will do what follows:

1. Go to "System" -> "License" -> "Get key Freely"
2. Click on "Download Public License"
3. We download the "ZKAcces3.5 Public License" and it will ask us to register on the ZKTeco page
4. Once the login is done, it will allow us to download a .txt file with a serial number, which we will later have to put in "Use Public Key"