Hi @guenni
I’ve been deliberately quiet on this subject because I knew this page was coming: Community Documentation - Remote BLF’s using PJSIP
The above page outlines how to configure 2 FreePBX and/or PBXact systems using a current version of Asterisk 16+ and PJSIP extensions to share extension states across multiple systems. It was prepared by Sangoma support engineer @jackcampbell. As this is real time using native Asterisk functionality, it pretty much supersedes any previous methods based on polling scripts.