diff --git a/src/TinyGsmClientA6.h b/src/TinyGsmClientA6.h
index bca20c1..ab37837 100644
--- a/src/TinyGsmClientA6.h
+++ b/src/TinyGsmClientA6.h
@@ -189,7 +189,6 @@ public:
    */
 
   bool init(const char* pin = NULL) {
-    DBG(GF("### Modem Defined:"), getModemName());
     if (!testAT()) {
       return false;
     }
@@ -197,12 +196,11 @@ public:
     if (waitResponse() != 1) {
       return false;
     }
-    sendAT(GF("+CMEE=0"));
+    sendAT(GF("+CMEE=0"));  // Turn of verbose errors
     waitResponse();
-
-    sendAT(GF("+CMER=3,0,0,2"));
+    sendAT(GF("+CMER=3,0,0,2"));  // Set unsolicited result code output destination
     waitResponse();
-
+    DBG(GF("### Modem:"), getModemName());
     getSimStatus();
     return true;
   }
diff --git a/src/TinyGsmClientBG96.h b/src/TinyGsmClientBG96.h
index 78ef722..30c17e2 100644
--- a/src/TinyGsmClientBG96.h
+++ b/src/TinyGsmClientBG96.h
@@ -213,7 +213,6 @@ public:
    */
 
   bool init(const char* pin = NULL) {
-    DBG(GF("### Modem Defined:"), getModemName());
     if (!testAT()) {
       return false;
     }
@@ -221,6 +220,7 @@ public:
     if (waitResponse() != 1) {
       return false;
     }
+    DBG(GF("### Modem:"), getModemName());
     getSimStatus();
     return true;
   }
diff --git a/src/TinyGsmClientESP8266.h b/src/TinyGsmClientESP8266.h
index 8718aa8..fa75abe 100644
--- a/src/TinyGsmClientESP8266.h
+++ b/src/TinyGsmClientESP8266.h
@@ -206,7 +206,6 @@ public:
    */
 
   bool init(const char* pin = NULL) {
-    DBG(GF("### Modem Defined:"), getModemName());
     if (!testAT()) {
       return false;
     }
@@ -222,6 +221,7 @@ public:
     if (waitResponse() != 1) {
       return false;
     }
+    DBG(GF("### Modem:"), getModemName());
     return true;
   }
 
diff --git a/src/TinyGsmClientM590.h b/src/TinyGsmClientM590.h
index c289ad1..b2eb97d 100644
--- a/src/TinyGsmClientM590.h
+++ b/src/TinyGsmClientM590.h
@@ -186,7 +186,6 @@ public:
    */
 
   bool init(const char* pin = NULL) {
-    DBG(GF("### Modem Defined:"), getModemName());
     if (!testAT()) {
       return false;
     }
@@ -198,7 +197,7 @@ public:
     sendAT(GF("+CMEE=2"));
     waitResponse();
 #endif
-
+    DBG(GF("### Modem:"), getModemName());
     getSimStatus();
     return true;
   }
diff --git a/src/TinyGsmClientM95.h b/src/TinyGsmClientM95.h
index 325028f..1b9e869 100644
--- a/src/TinyGsmClientM95.h
+++ b/src/TinyGsmClientM95.h
@@ -213,7 +213,6 @@ public:
    */
 
   bool init(const char* pin = NULL) {
-    DBG(GF("### Modem Defined:"), getModemName());
     if (!testAT()) {
       return false;
     }
@@ -225,7 +224,7 @@ public:
     sendAT(GF("+CMEE=2"));
     waitResponse();
 #endif
-
+    DBG(GF("### Modem:"), getModemName());
     getSimStatus();
     return true;
   }
@@ -329,6 +328,8 @@ public:
     return true;
   }
 
+  bool sleepEnable(bool enable = true) TINY_GSM_ATTR_NOT_IMPLEMENTED;
+
   /*
    * SIM card functions
    */
@@ -644,14 +645,11 @@ public:
 protected:
 
   bool modemConnect(const char* host, uint16_t port, uint8_t mux, bool ssl = false) {
-    sendAT(GF("+QIOPEN="), GF("\"TCP"), GF("\",\""), host, GF("\","), port);
+    sendAT(GF("+QIOPEN="), mux, GF("\"TCP"), GF("\",\""), host, GF("\","), port);
     int rsp = waitResponse(75000L,
                            GF("CONNECT OK" GSM_NL),
                            GF("CONNECT FAIL" GSM_NL),
                            GF("ALREADY CONNECT" GSM_NL));
-    if ( rsp != 1 ) {
-      return false;
-    }
     return (1 == rsp);
   }
 
diff --git a/src/TinyGsmClientMC60.h b/src/TinyGsmClientMC60.h
index 1b33bcc..265cd4b 100644
--- a/src/TinyGsmClientMC60.h
+++ b/src/TinyGsmClientMC60.h
@@ -217,7 +217,6 @@ public:
    */
 
   bool init(const char* pin = NULL) {
-    DBG(GF("### Modem Defined:"), getModemName());
     if (!testAT()) {
       return false;
     }
@@ -227,6 +226,7 @@ public:
     if (waitResponse() != 1) {
       return false;
     }
+    DBG(GF("### Modem:"), getModemName());
     getSimStatus();
     return true;
   }
@@ -350,6 +350,8 @@ public:
     return true;
   }
 
+  bool sleepEnable(bool enable = true) TINY_GSM_ATTR_NOT_IMPLEMENTED;
+
   /*
    * SIM card functions
    */
@@ -671,14 +673,11 @@ public:
 protected:
 
   bool modemConnect(const char* host, uint16_t port, uint8_t mux, bool ssl = false) {
-    sendAT(GF("+QIOPEN="), GF("\"TCP"), GF("\",\""), host, GF("\","), port);
+    sendAT(GF("+QIOPEN="), mux, GF("\"TCP"), GF("\",\""), host, GF("\","), port);
     int rsp = waitResponse(75000L,
                            GF("CONNECT OK" GSM_NL),
                            GF("CONNECT FAIL" GSM_NL),
                            GF("ALREADY CONNECT" GSM_NL));
-    if ( rsp != 1 ) {
-      return false;
-    }
     return (1 == rsp);
   }
 
diff --git a/src/TinyGsmClientSIM800.h b/src/TinyGsmClientSIM800.h
index 165b03d..24fcacb 100644
--- a/src/TinyGsmClientSIM800.h
+++ b/src/TinyGsmClientSIM800.h
@@ -227,7 +227,6 @@ public:
    */
 
   bool init(const char* pin = NULL) {
-    DBG(GF("### Modem Defined:"), getModemName());
     if (!testAT()) {
       return false;
     }
@@ -237,6 +236,7 @@ public:
     if (waitResponse() != 1) {
       return false;
     }
+    DBG(GF("### Modem:"), getModemName());
     getSimStatus();
     return true;
   }
diff --git a/src/TinyGsmClientUBLOX.h b/src/TinyGsmClientUBLOX.h
index cf9a62e..8afb3f3 100644
--- a/src/TinyGsmClientUBLOX.h
+++ b/src/TinyGsmClientUBLOX.h
@@ -212,7 +212,6 @@ public:
    */
 
   bool init(const char* pin = NULL) {
-    DBG(GF("### Modem Defined:"), getModemName());
     if (!testAT()) {
       return false;
     }
@@ -220,6 +219,7 @@ public:
     if (waitResponse() != 1) {
       return false;
     }
+    DBG(GF("### Modem:"), getModemName());
     int ret = getSimStatus();
     if (ret != SIM_READY && pin != NULL && strlen(pin) > 0) {
       simUnlock(pin);
@@ -228,7 +228,7 @@ public:
   }
 
   String getModemName() {
-    sendAT(GF("CGMI"));
+    sendAT(GF("+CGMI"));
     String res1;
     if (waitResponse(1000L, res1) != 1) {
       return "u-blox Cellular Modem";
@@ -237,7 +237,7 @@ public:
     res1.replace(GSM_NL, " ");
     res1.trim();
 
-    sendAT(GF("GMM"));
+    sendAT(GF("+GMM"));
     String res2;
     if (waitResponse(1000L, res1) != 1) {
       return "u-blox Cellular Modem";
@@ -589,8 +589,8 @@ public:
 protected:
 
   bool modemConnect(const char* host, uint16_t port, uint8_t* mux, bool ssl = false) {
-    sendAT(GF("+USOCR=6"));
-    if (waitResponse(GF(GSM_NL "+USOCR:")) != 1) {
+    sendAT(GF("+USOCR=6"));  // create a socket
+    if (waitResponse(GF(GSM_NL "+USOCR:")) != 1) {  // reply is +USOCR: ## of socket created
       return false;
     }
     *mux = stream.readStringUntil('\n').toInt();
@@ -609,7 +609,7 @@ protected:
     //sendAT(GF("+USOSO="), *mux, GF(",6,2,30000"));
     //waitResponse();
 
-    sendAT(GF("+USOCO="), *mux, ",\"", host, "\",", port);
+    sendAT(GF("+USOCO="), *mux, ",\"", host, "\",", port);  // connect on socket
     int rsp = waitResponse(75000L);
     return (1 == rsp);
   }