Swissphone DiCal-RED 4009 devices allow an unauthenticated attacker use a port-2101 TCP connection to gain access to operation messages that are received by the device.
https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2024-042.txt
https://www.swissphone.com/en-us/solutions/components/terminals/radio-data-module-dical-red/