diff --git a/TinyGsmClientU201.h b/TinyGsmClientU201.h
index fd4a587..27827cf 100644
--- a/TinyGsmClientU201.h
+++ b/TinyGsmClientU201.h
@@ -434,7 +434,7 @@ public:
     if (res != 1)
       return false;
 
-    sendAT(GF("+CIFSR;E0")); // Another option is to use AT+CGPADDR=1
+    sendAT(GF("+CIFSR"));
     if (waitResponse() != 1)
       return false;
 
@@ -459,24 +459,12 @@ public:
    * Phone Call functions
    */
 
-  bool setGsmBusy(bool busy = true) {
-    sendAT(GF("+GSMBUSY="), busy ? 1 : 0);
-    return waitResponse() == 1;
-  }
+  bool setGsmBusy(bool busy = true) TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
-  bool callAnswer() {
-    sendAT(GF("A"));
-    return waitResponse() == 1;
-  }
+  bool callAnswer() TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
-  // Returns true on pick-up, false on error/busy
   bool callNumber(const String& number) TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
-  //bool callRedial() {
-  //  sendAT(GF("DL"));
-  //  return waitResponse() == 1;
-  //}
-
   bool callHangup() TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
   /*