Update TinyGsmClientSIM800.h

implementation of audio capabilities

src/TinyGsmClientSIM800.h

@@ -445,6 +445,46 @@ class TinyGsmSim800 : public TinyGsmModem<TinyGsmSim800>,
  protected:
   // No functions of this type supported
 
+  /*
+   * Audio functions
+   */
+ public:
+  bool setVolume(uint8_t volume = 50){
+	//Set speaker volume
+    sendAT(GF("+CLVL="), volume);
+    return waitResponse() == 1;
+  }
+  
+  uint8_t getVolume(){
+	//Get speaker volume
+	sendAT(GF("+CLVL?"));
+	if (waitResponse(GF(GSM_NL)) != 1) { return 0; }
+    String res = stream.readStringUntil('\n');
+	waitResponse();
+	res.replace("+CLVL:", "");
+    res.trim();
+	return res.toInt();
+  }
+  
+  bool setMicVolume(uint8_t channel, uint8_t level){
+    if(channel > 4){
+	  return 0;
+	}
+    sendAT(GF("+CMIC="), level);
+    return waitResponse() == 1;
+  }
+  
+  bool setAudioChannel(uint8_t channel){
+    sendAT(GF("+CHFA="), channel);
+    return waitResponse() == 1;
+  }
+  
+  bool playToolkitTone(uint8_t tone, uint32_t duration){
+    sendAT(GF("STTONE="), 1, tone);
+	delay(duration);
+	sendAT(GF("STTONE="), 0);
+	return waitResponse();
+  }
   /*
    * Time functions
    */