diff --git a/src/TinyGsmClientA6.h b/src/TinyGsmClientA6.h
index 5cb0e34..42760d4 100644
--- a/src/TinyGsmClientA6.h
+++ b/src/TinyGsmClientA6.h
@@ -457,6 +457,88 @@ public:
     return res;
   }
 
+  /*
+   * Phone Call functions
+   */
+
+  bool setGsmBusy(bool busy = true) TINY_GSM_ATTR_NOT_AVAILABLE;
+
+  bool callAnswer() {
+    sendAT(GF("A"));
+    return waitResponse() == 1;
+  }
+
+  // Returns true on pick-up, false on error/busy
+  bool callNumber(const String& number) {
+    if (number == GF("last")) {
+      sendAT(GF("DLST"));
+    } else {
+      sendAT(GF("D\""), number, "\";");
+    }
+
+    if (waitResponse(5000L) != 1) {
+      return false;
+    }
+
+    if (waitResponse(60000L,
+        GF(GSM_NL "+CIEV: \"CALL\",1"),
+        GF(GSM_NL "+CIEV: \"CALL\",0"),
+        GFP(GSM_ERROR)) != 1)
+    {
+      return false;
+    }
+
+    int rsp = waitResponse(60000L,
+              GF(GSM_NL "+CIEV: \"SOUNDER\",0"),
+              GF(GSM_NL "+CIEV: \"CALL\",0"));
+
+    int rsp2 = waitResponse(300L, GF(GSM_NL "BUSY" GSM_NL), GF(GSM_NL "NO ANSWER" GSM_NL));
+
+    return rsp == 1 && rsp2 == 0;
+  }
+
+  bool callHangup() {
+    sendAT(GF("H"));
+    return waitResponse() == 1;
+  }
+
+  // 0-9,*,#,A,B,C,D
+  bool dtmfSend(char cmd, unsigned duration_ms = 100) {
+    duration_ms = constrain(duration_ms, 100, 1000);
+
+    // The duration parameter is not working, so we simulate it using delay..
+    // TODO: Maybe there's another way...
+
+    //sendAT(GF("+VTD="), duration_ms / 100);
+    //waitResponse();
+
+    sendAT(GF("+VTS="), cmd);
+    if (waitResponse(10000L) == 1) {
+      delay(duration_ms);
+      return true;
+    }
+    return false;
+  }
+
+  /*
+   * Audio functions
+   */
+
+  bool audioSetHeadphones() {
+    sendAT(GF("+SNFS=0"));
+    return waitResponse() == 1;
+  }
+
+  bool audioSetSpeaker() {
+    sendAT(GF("+SNFS=1"));
+    return waitResponse() == 1;
+  }
+
+  bool audioMuteMic(bool mute) {
+    sendAT(GF("+CMUT="), mute);
+    return waitResponse() == 1;
+  }
+
   /*
    * Messaging functions
    */
diff --git a/src/TinyGsmClientBG96.h b/src/TinyGsmClientBG96.h
index be7e7aa..ac76365 100644
--- a/src/TinyGsmClientBG96.h
+++ b/src/TinyGsmClientBG96.h
@@ -474,6 +474,36 @@ public:
     return res;
   }
 
+  /*
+   * Phone Call functions
+   */
+
+  bool setGsmBusy(bool busy = true) TINY_GSM_ATTR_NOT_AVAILABLE;
+
+  bool callAnswer() {
+    sendAT(GF("A"));
+    return waitResponse() == 1;
+  }
+
+  // Returns true on pick-up, false on error/busy
+  bool callNumber(const String& number) TINY_GSM_ATTR_NOT_IMPLEMENTED;
+
+  bool callHangup() {
+    sendAT(GF("H"));
+    return waitResponse() == 1;
+  }
+
+  // 0-9,*,#,A,B,C,D
+  bool dtmfSend(char cmd, int duration_ms = 100) { // TODO: check
+    duration_ms = constrain(duration_ms, 100, 1000);
+
+    sendAT(GF("+VTD="), duration_ms / 100); // VTD accepts in 1/10 of a second
+    waitResponse();
+
+    sendAT(GF("+VTS="), cmd);
+    return waitResponse(10000L) == 1;
+  }
+
   /*
    * Messaging functions
    */
diff --git a/src/TinyGsmClientM590.h b/src/TinyGsmClientM590.h
index d56f319..d919a17 100644
--- a/src/TinyGsmClientM590.h
+++ b/src/TinyGsmClientM590.h
@@ -458,6 +458,18 @@ public:
     return res;
   }
 
+  /*
+   * Phone Call functions
+   */
+
+  bool setGsmBusy(bool busy = true) TINY_GSM_ATTR_NOT_AVAILABLE;
+
+  bool callAnswer() TINY_GSM_ATTR_NOT_AVAILABLE;
+
+  bool callNumber(const String& number) TINY_GSM_ATTR_NOT_AVAILABLE;
+
+  bool callHangup() TINY_GSM_ATTR_NOT_AVAILABLE;
+
   /*
    * Messaging functions
    */
diff --git a/src/TinyGsmClientM95.h b/src/TinyGsmClientM95.h
index 085ddae..6b01da1 100644
--- a/src/TinyGsmClientM95.h
+++ b/src/TinyGsmClientM95.h
@@ -593,6 +593,14 @@ public:
     return false;
   }
 
+  /*
+   * Phone Call functions
+   */
+
+  bool setGsmBusy(bool busy = true) TINY_GSM_ATTR_NOT_AVAILABLE;
+  bool callAnswer() TINY_GSM_ATTR_NOT_AVAILABLE;
+  bool callNumber(const String& number) TINY_GSM_ATTR_NOT_AVAILABLE;
+  bool callHangup() TINY_GSM_ATTR_NOT_AVAILABLE;
 
   /*
    * Location functions
diff --git a/src/TinyGsmClientSIM800.h b/src/TinyGsmClientSIM800.h
index e58f6f5..e34020d 100644
--- a/src/TinyGsmClientSIM800.h
+++ b/src/TinyGsmClientSIM800.h
@@ -40,6 +40,11 @@ enum RegStatus {
   REG_UNKNOWN      = 4,
 };
 
+enum TinyGSMDateTimeFormat {
+  DATE_FULL = 0,
+  DATE_TIME = 1,
+  DATE_DATE = 2
+};
 
 class TinyGsmSim800 : public TinyGsmModem
 {
@@ -605,6 +610,57 @@ public:
     return res;
   }
 
+
+  /*
+   * Phone Call functions
+   */
+
+  bool setGsmBusy(bool busy = true) {
+    sendAT(GF("+GSMBUSY="), busy ? 1 : 0);
+    return waitResponse() == 1;
+  }
+
+  bool callAnswer() {
+    sendAT(GF("A"));
+    return waitResponse() == 1;
+  }
+
+  // Returns true on pick-up, false on error/busy
+  bool callNumber(const String& number) {
+    if (number == GF("last")) {
+      sendAT(GF("DL"));
+    } else {
+      sendAT(GF("D"), number, ";");
+    }
+    int status = waitResponse(60000L,
+                              GFP(GSM_OK),
+                              GF("BUSY" GSM_NL),
+                              GF("NO ANSWER" GSM_NL),
+                              GF("NO CARRIER" GSM_NL));
+    switch (status) {
+    case 1:  return true;
+    case 2:
+    case 3:  return false;
+    default: return false;
+    }
+  }
+
+  bool callHangup() {
+    sendAT(GF("H"));
+    return waitResponse() == 1;
+  }
+
+  // 0-9,*,#,A,B,C,D
+  bool dtmfSend(char cmd, int duration_ms = 100) {
+    duration_ms = constrain(duration_ms, 100, 1000);
+
+    sendAT(GF("+VTD="), duration_ms / 100); // VTD accepts in 1/10 of a second
+    waitResponse();
+
+    sendAT(GF("+VTS="), cmd);
+    return waitResponse(10000L) == 1;
+  }
+
   /*
    * Messaging functions
    */
@@ -694,6 +750,32 @@ public:
     return res;
   }
 
+  /*
+   * Time functions
+   */
+  String getGSMDateTime(TinyGSMDateTimeFormat format) {
+    sendAT(GF("+CCLK?"));
+    if (waitResponse(2000L, GF(GSM_NL "+CCLK: \"")) != 1) {
+      return "";
+    }
+
+    String res;
+
+    switch(format) {
+      case DATE_FULL:
+        res = stream.readStringUntil('"');
+      break;
+      case DATE_TIME:
+        streamSkipUntil(',');
+        res = stream.readStringUntil('"');
+      break;
+      case DATE_DATE:
+        res = stream.readStringUntil(',');
+      break;
+    }
+    return res;
+  }
+
   /*
    * Battery functions
    */
diff --git a/src/TinyGsmClientUBLOX.h b/src/TinyGsmClientUBLOX.h
index a37eb7c..48556d5 100644
--- a/src/TinyGsmClientUBLOX.h
+++ b/src/TinyGsmClientUBLOX.h
@@ -494,6 +494,18 @@ public:
     return res;
   }
 
+  /*
+   * Phone Call functions
+   */
+
+  bool setGsmBusy(bool busy = true) TINY_GSM_ATTR_NOT_AVAILABLE;
+
+  bool callAnswer() TINY_GSM_ATTR_NOT_IMPLEMENTED;
+
+  bool callNumber(const String& number) TINY_GSM_ATTR_NOT_IMPLEMENTED;
+
+  bool callHangup() TINY_GSM_ATTR_NOT_IMPLEMENTED;
+
   /*
    * Messaging functions
    */