- Allow COMn_VLT to be literal strings "true" or "false"

- FGFS: simplify protocol file.
  the "operable" property is a common one and honors powered, turned on and serviceable.
  see: https://forum.flightgear.org/viewtopic.php?p=382015#p382015
- FGFS: Support standard squelch property

client/fgfs/Protocol/fgcom-mumble.xml

@@ -54,25 +54,13 @@
     <format>COM1_CWKHZ=%s</format>
     <node>/instrumentation/comm[0]/frequencies/selected-channel-width-khz</node>
    </chunk>
-   <chunk>
-    <name>com1-powered</name>
-    <type>string</type>
-    <format>COM1_VLT=%s</format> <!-- in volts -->
-    <node>/system/electrical/outputs/comm[0]</node>
-   </chunk>
    <chunk>
     <name>com1-powerbutton</name>
     <type>string</type>
     <format>COM1_PBT=%s</format> <!-- 0=inactive, 1=active -->
-    <node>/instrumentation/comm[0]/power-btn</node>
+    <node>/instrumentation/comm[0]/operable</node>
+    <!-- ^^ we use the operable property because it honors all conditions (powered, serviceable, turned on) --->
    </chunk>
-   <chunk>
-    <name>com1-serviceable</name>
-    <type>string</type>
-    <format>COM1_SRV=%s</format> <!-- 0=failed, 1=operable -->
-    <node>/instrumentation/comm[0]/serviceable</node>
-   </chunk>
-   <chunk>
     <name>com1-ptt</name>
     <type>string</type>
     <format>COM1_PTT=%s</format> <!-- 0=inactive, 1=active -->
@@ -94,7 +82,7 @@
     <name>com1-squelch</name>
     <type>string</type>
     <format>COM1_SQC=%s</format> <!-- 0.0=cutoff nothing, 1.0=cutoff any -->
-    <node>/instrumentation/comm[0]/squelch</node>
+    <node>/instrumentation/comm[0]/cutoff-signal-quality</node>
    </chunk>
 
    <!-- COM 2 -->
@@ -110,23 +98,12 @@
     <format>COM2_CWKHZ=%s</format>
     <node>/instrumentation/comm[1]/frequencies/selected-channel-width-khz</node>
    </chunk>
-   <chunk>
-    <name>com2-powered</name>
-    <type>string</type>
-    <format>COM2_VLT=%s</format> <!-- in volts -->
-    <node>/system/electrical/outputs/comm[1]</node>
-   </chunk>
    <chunk>
     <name>com2-powerbutton</name>
     <type>string</type>
     <format>COM2_PBT=%s</format> <!-- 0=inactive, 1=active -->
-    <node>/instrumentation/comm[1]/power-btn</node>
-   </chunk>
-   <chunk>
-    <name>com2-serviceable</name>
-    <type>string</type>
-    <format>COM2_SRV=%s</format> <!-- 0=failed, 1=operable -->
-    <node>/instrumentation/comm[1]/serviceable</node>
+    <node>/instrumentation/comm[1]/operable</node>
+    <!-- ^^ we use the operable property because it honors all conditions (powered, serviceable, turned on) --->
    </chunk>
    <chunk>
     <name>com2-ptt</name>
@@ -150,7 +127,7 @@
     <name>com2-squelch</name>
     <type>string</type>
     <format>COM1_SQC=%s</format> <!-- 0.0=cutoff nothing, 1.0=cutoff any -->
-    <node>/instrumentation/comm[1]/squelch</node>
+    <node>/instrumentation/comm[1]/cutoff-signal-quality</node>
    </chunk>
 
 

client/mumble-plugin/lib/io_UDPServer.cpp

@@ -252,7 +252,12 @@ std::map<int, fgcom_udp_parseMsg_result> fgcom_udp_parseMsg(char buffer[MAXLINE]
                     }
                     if (radio_var == "VLT") {
                         float oldValue = fgcom_local_client[iid].radios[radio_id].volts;
-                        fgcom_local_client[iid].radios[radio_id].volts       = std::stof(token_value);
+                        if (token_value == "true" || token_value == "false") {
+                            // support literal strings in case aircraft sends just a boolean as string
+                            fgcom_local_client[iid].radios[radio_id].volts = (token_value == "true")? true : false;
+                        } else {
+                            fgcom_local_client[iid].radios[radio_id].volts       = std::stof(token_value);
+                        }
                         // do not send right now: if (fgcom_local_client[iid].radios[radio_id].volts != oldValue ) parseResult[iid].radioData.insert(radio_id);
                     }
                     if (radio_var == "PBT") {