An Electronic Shelf Label is a device that's typically attached to the front edge of retail shelving.
ESL Firebase Edition V2.0 utilizes the AES-256 in CBC mode and Google Firebase. It doesn't require an expensive gateway to function, once configured, all it needs is a power supply and a Wi-Fi access point.
ESL Firebase Edition V2.0 allows you to operate as many of them as you wish, provided that each has its own unique ID, and there's enough power and bandwidth for all of them.
For...
RadicalSpam is a free and open source package distributed under GPL v2, including products such as Postfix, SpamAssassin Amavisd-new, Clamav, Razor, DCC, Postgrey, Bind; providing a secure SMTP relay, ready to use with linux and docker environement. More information : http://www.radical-spam.org