Intelligent Hotel Door Bell, (Buspro)
https://b2b.hdl-automation.cz/en/support/products/data-sheets/buspro/hotel-system/hdl-mhb-1010(sb-3s-bell)
https://b2b.hdl-automation.cz/en/support/products/data-sheets/buspro/hotel-system/hdl-mhb-1010(sb-3s-bell)