diff --git a/backend/src/routes/telephony.ts b/backend/src/routes/telephony.ts
index 0c6258e..2c0e6c1 100644
--- a/backend/src/routes/telephony.ts
+++ b/backend/src/routes/telephony.ts
@@ -304,7 +304,8 @@ const writeAsteriskTrunkConfig = async (trunk: any) => {
 
     await Promise.all(files.map(async (file) => {
         const target = path.join(targetDir, file.name)
-        await fs.writeFile(target, `${file.content}\n`, { mode: 0o600 })
+        await fs.writeFile(target, `${file.content}\n`, { mode: 0o644 })
+        await fs.chmod(target, 0o644)
     }))
 
     return files.map((file) => path.join(targetDir, file.name))
diff --git a/telephony/render-asterisk-config.sh b/telephony/render-asterisk-config.sh
index 1b0f8e5..ceb108a 100755
--- a/telephony/render-asterisk-config.sh
+++ b/telephony/render-asterisk-config.sh
@@ -10,6 +10,12 @@ EXTENSIONS_FILE="$GENERATED_DIR/extensions.telekom.conf"
 enabled="${TELEPHONY_TELEKOM_ENABLED:-false}"
 
 if [ "$enabled" != "true" ] && [ "$enabled" != "1" ] && [ "$enabled" != "yes" ]; then
+  if grep -q "Von FEDEO generiert" "$PJSIP_FILE" 2>/dev/null \
+    && ! grep -q "Telekom-Trunk ist deaktiviert" "$PJSIP_FILE" 2>/dev/null; then
+    echo "FEDEO Telefonie: bestehende FEDEO-Trunk-Konfiguration bleibt erhalten."
+    exit 0
+  fi
+
   cat > "$PJSIP_FILE" <<'EOF'
 ; Telekom-Anbindung ist deaktiviert.
 EOF