TaHoma switch is a smart command to centralize and connect your Somfy and other brands home equipment. It is compatible with three radio protocols : io home-control, RTS and Zigbee 3.0. It also allows Cloud and Voice Assistants compatibilities. TaHoma switch is linked to the new TaHoma app, which allows the creation of manual, planned and advanced scenes and many other features.
Connectivity kit is the gateway to control Somfy motorizations and lighting from the TaHoma app or by voice (with an additional Voice Assistant). The Connectivity kit uses two Somfy radio protocols : io home-control and RTS. Even though they use the same app, the Connectivity kit offers less features than TaHoma switch, for example, only manual scenes can be created.
Other limitations apply to the Connectivity kit, more information are available here :