diff --git a/src/DTE.h b/src/DTE.h
index a20dc54..154f9d2 100644
--- a/src/DTE.h
+++ b/src/DTE.h
@@ -15,14 +15,12 @@ class DTE {
         EXPECT_BUSY,
         EXPECT_TIMEOUT,
         EXPECT_DELAY,
-        EXPECT_RESULT,
-        EXPECT_RING
+        EXPECT_RESULT
     };
 
   private:
     String buffer;
     Stream & stream;
-    unsigned int bufferIndex;
     unsigned int bufferSize;
     String response[3];
     unsigned long timeout;
@@ -39,7 +37,7 @@ class DTE {
 
     ~DTE() = default;
 
-    void SendCommand(const char * command, unsigned long timeout, const char * response1, const char * response2 = 0, const char * response3 = 0)
+    void SendCommand(const char * command, unsigned long timeout, const char * response1, const char * response2 = nullptr, const char * response3 = nullptr)
     {
         match = 0;
         result = EXPECT_BUSY;
@@ -54,7 +52,7 @@ class DTE {
         proccess();
     }
 
-    void SendCommand(const __FlashStringHelper * command, unsigned long timeout, const char * response1, const char * response2 = 0, const char * response3 = 0)
+    void SendCommand(const __FlashStringHelper * command, unsigned long timeout, const char * response1, const char * response2 = nullptr, const char * response3 = nullptr)
     {
 
         match = 0;
@@ -119,21 +117,8 @@ class DTE {
             return;
         }
 
-        if (result != EXPECT_BUSY) {
-            if (stream.available()) {
-                char c;
-
-                c = stream.read();
-                buffer += c;
-                if (buffer.length() > 4) {
-                    if (buffer.endsWith(F("RING\n"))) {
-                        result = EXPECT_RING;
-                    }
-                    buffer.remove(0);
-                }
-            }
+        if (result != EXPECT_BUSY)
             return;
-        }
 
         char c;
         unsigned long now = millis();
@@ -141,7 +126,7 @@ class DTE {
         while (millis() - tick < timeout) {
             while (stream.available() && (buffer.length() < bufferSize)) {
                 c = stream.read();
-                buffer += c;
+                buffer.concat(c);
                 if (buffer.endsWith(response[0])) {
                     match = 0;
                     result = EXPECT_RESULT;
diff --git a/src/ThreadedGSM.h b/src/ThreadedGSM.h
index 0828bb2..badf514 100644
--- a/src/ThreadedGSM.h
+++ b/src/ThreadedGSM.h
@@ -676,10 +676,6 @@ class ThreadedGSM {
         int lastState = ringState;
         switch (ringState) {
             case RING_WAIT:
-                if (dte.getResult() == DTE::EXPECT_RING) {
-
-                    ringState = RING_CHK;
-                }
                 break;
 
             case RING_CHK: