The SkyEcho2 is classed as an EC device providing both ADS-B IN and OUT.

What are its limitations?

EC systems are designed for aircraft-to-aircraft traffic awareness. An EC device will not meet standards to allow you to enter controlled airspace in which a transponder is mandatory or to fly in a transponder mandatory zone (TMZ). EC device transmissions must be deactivated when used in an aircraft equipped with an operating Extended Squitter (ES) ADS-B OUT transponder.

Installation et mode d’emploi de SkyEcho2: https://uavionix.com/downloads/skyecho/SkyEcho-User-and-Installation-Guide-REV-I.pdf

SkyEcho2 et Skydemon: https://www.unmannedtechshop.co.uk/wp-content/uploads/2018/12/Configure-SkyDemon-for-Sky-Echo-2.pdf