diff --git a/README.md b/README.md
index f7fc0db..eb7a825 100644
--- a/README.md
+++ b/README.md
@@ -35,20 +35,20 @@ TinyGSM also pulls data gently from the modem (whenever possible), so it can ope
 
 ## Features
 
-Feature \ Modem              | SIM8xx | Ublox  | A6/A7/A20 | M590 | ESP8266 | XBee 
+Feature \ Modem              | SIM8xx | u-Blox | A6/A7/A20 | M590 | ESP8266 | XBee
 ---                          | ---    | ---    | ---       | ---  | ---     | ---
 **Data connections**
 TCP (HTTP, MQTT, Blynk, ...) | ✔      | ✔      | ✔         | ✔    | ✔       | ✔
 UDP                          | ◌      | ◌      |           |      |         | ◌
 SSL/TLS (HTTPS)              | ✔¹     | ✔      | 🅧        | 🅧    | ✔¹      | ✔¹
 **USSD**
-Sending USSD requests        | ✔      |        | ✔         | ✔    | 🅧       | 
-Decoding 7,8,16-bit response | ✔      |        | ✔         | ✔    | 🅧      | 
+Sending USSD requests        | ✔      |        | ✔         | ✔    | 🅧       |
+Decoding 7,8,16-bit response | ✔      |        | ✔         | ✔    | 🅧      |
 **SMS**
-Sending                      | ✔      |        | ✔         | ✔    | 🅧      | ✔
-Sending Unicode              | ✔      |        | ◌         | 🅧   | 🅧      | 
-Reading                      |        |        |           |      | 🅧      | 
-Incoming message event       |        |        |           | ?    | 🅧      | 
+Sending                      | ✔      | ✔      | ✔         | ✔    | 🅧      | ✔
+Sending Unicode              | ✔      |        | ◌         | 🅧   | 🅧      |
+Reading                      |        |        |           |      | 🅧      |
+Incoming message event       |        |        |           | ?    | 🅧      |
 **Calls**
 Dial, hangup                 | ✔      |        | ✔         | 🅧   | 🅧      | 🅧
 Receiving calls              | ✔      |        | ✔         | 🅧   | 🅧      | 🅧
@@ -70,7 +70,7 @@ GPS/GNSS                     | ✔¹     | 🅧     | ◌¹        | 🅧   | 
 - ESP8266 (AT commands interface, similar to GSM modems)
 - Digi XBee WiFi and Cellular (using XBee command mode)
 - Neoway M590
-- U-blox SARA U2 (U201, U260, U270)
+- u-blox Cellular Modems (LEON-G100, LISA-U2xx, SARA-G3xx, SARA-U2xx, TOBY-L2xx, LARA-R2xx, MPCI-L2xx)
 - Quectel BG96 ***(alpha)***
 
 ### Supported boards/modules
@@ -141,7 +141,7 @@ For additional functions, please refer to [this example sketch](examples/AllFunc
 
 Use this sketch to diagnose your SIM card and GPRS connection:  
   File -> Examples -> TynyGSM -> tools -> [Diagnostics](https://github.com/vshymanskyy/TinyGSM/blob/master/tools/Diagnostics/Diagnostics.ino)
-  
+
 ### Ensure stable data & power connection
 
 Most modules require up to 2A and specific voltage - according to the module documentation.
@@ -158,7 +158,7 @@ Try selecting **57600**, **38400**, or even lower - the one that works best for
 In some cases **9600** is unstable, but using **38400** helps, etc.  
 Be sure to set correct TX/RX pins in the sketch. Please note that not every Arduino pin can serve as TX or RX pin.  
 **Read more about SoftSerial options and configuration [here](https://www.pjrc.com/teensy/td_libs_AltSoftSerial.html) and [here](https://www.arduino.cc/en/Reference/SoftwareSerial).**
-  
+
 ### ESP32 HardwareSerial
 
 When using ESP32 `HardwareSerial`, you may need to specify additional parameters to the `.begin()` call.
@@ -180,7 +180,7 @@ This may result in problems such as:
  * etc.
 
 To return module to **Factory Defaults**, use this sketch:  
-  File -> Examples -> TynyGSM -> tools -> [FactoryReset](https://github.com/vshymanskyy/TinyGSM/blob/master/tools/FactoryReset/FactoryReset.ino)
+  File -> Examples -> TinyGSM -> tools -> [FactoryReset](https://github.com/vshymanskyy/TinyGSM/blob/master/tools/FactoryReset/FactoryReset.ino)
 
 ### Goouuu Tech IOT-GA6 vs AI-Thinker A6 confusion
 
diff --git a/src/TinyGsmClient.h b/src/TinyGsmClient.h
index 8c73bce..c352cbb 100644
--- a/src/TinyGsmClient.h
+++ b/src/TinyGsmClient.h
@@ -34,9 +34,9 @@
 #elif defined(TINY_GSM_MODEM_UBLOX)
   #define TINY_GSM_MODEM_HAS_GPRS
   #include <TinyGsmClientUBLOX.h>
-  typedef TinyGsmU201 TinyGsm;
-  typedef TinyGsmU201::GsmClient TinyGsmClient;
-  typedef TinyGsmU201::GsmClientSecure TinyGsmClientSecure;
+  typedef TinyGsmUBLOX TinyGsm;
+  typedef TinyGsmUBLOX::GsmClient TinyGsmClient;
+  typedef TinyGsmUBLOX::GsmClientSecure TinyGsmClientSecure;
 
 #elif defined(TINY_GSM_MODEM_BG96)
   #define TINY_GSM_MODEM_HAS_GPRS
@@ -47,24 +47,29 @@
 #elif defined(TINY_GSM_MODEM_A6) || defined(TINY_GSM_MODEM_A7)
   #define TINY_GSM_MODEM_HAS_GPRS
   #include <TinyGsmClientA6.h>
-  typedef TinyGsm::GsmClient TinyGsmClient;
+  typedef TinyGsmA6 TinyGsm;
+  typedef TinyGsmA6::GsmClient TinyGsmClient;
 
 #elif defined(TINY_GSM_MODEM_M590)
   #define TINY_GSM_MODEM_HAS_GPRS
   #include <TinyGsmClientM590.h>
-  typedef TinyGsm::GsmClient TinyGsmClient;
+  typedef TinyGsmM590 TinyGsm;
+  typedef TinyGsmM590::GsmClient TinyGsmClient;
 
 #elif defined(TINY_GSM_MODEM_ESP8266)
   #define TINY_GSM_MODEM_HAS_WIFI
   #include <TinyGsmClientESP8266.h>
-  typedef TinyGsm::GsmClient TinyGsmClient;
-  typedef TinyGsm::GsmClientSecure TinyGsmClientSecure;
+  typedef TinyGsmESP8266 TinyGsm;
+  typedef TinyGsmESP8266::GsmClient TinyGsmClient;
+  typedef TinyGsmESP8266::GsmClientSecure TinyGsmClientSecure;
 
 #elif defined(TINY_GSM_MODEM_XBEE)
   #define TINY_GSM_MODEM_HAS_GPRS
   #define TINY_GSM_MODEM_HAS_WIFI
   #include <TinyGsmClientXBee.h>
-  typedef TinyGsm::GsmClient TinyGsmClient;
+  typedef TinyGsmXBee TinyGsm;
+  typedef TinyGsmXBee::GsmClient TinyGsmClient;
+  typedef TinyGsmXBee::GsmClientSecure TinyGsmClientSecure;
 
 #else
   #error "Please define GSM modem model"
diff --git a/src/TinyGsmClientA6.h b/src/TinyGsmClientA6.h
index a53890b..ef6414c 100644
--- a/src/TinyGsmClientA6.h
+++ b/src/TinyGsmClientA6.h
@@ -38,25 +38,37 @@ enum RegStatus {
   REG_UNKNOWN      = 4,
 };
 
+//============================================================================//
+//============================================================================//
+//                       Declaration of the TinyGsmA6 Class
+//============================================================================//
+//============================================================================//
 
-class TinyGsm
+class TinyGsmA6
 {
 
+//============================================================================//
+//============================================================================//
+//                          The Internal A6 Client Class
+//============================================================================//
+//============================================================================//
+
+
 public:
 
 class GsmClient : public Client
 {
-  friend class TinyGsm;
+  friend class TinyGsmA6;
   typedef TinyGsmFifo<uint8_t, TINY_GSM_RX_BUFFER> RxFifo;
 
 public:
   GsmClient() {}
 
-  GsmClient(TinyGsm& modem) {
+  GsmClient(TinyGsmA6& modem) {
     init(&modem);
   }
 
-  bool init(TinyGsm* modem) {
+  bool init(TinyGsmA6* modem) {
     this->at = modem;
     this->mux = -1;
     sock_connected = false;
@@ -162,15 +174,33 @@ public:
   String remoteIP() TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
 private:
-  TinyGsm*      at;
-  uint8_t       mux;
-  bool          sock_connected;
-  RxFifo        rx;
+  TinyGsmA6*      at;
+  uint8_t         mux;
+  bool            sock_connected;
+  RxFifo          rx;
 };
 
+//============================================================================//
+//============================================================================//
+//                      The A6 does not have a secure client!
+//============================================================================//
+//============================================================================//
+
+
+
+//============================================================================//
+//============================================================================//
+//                          The A6 Modem Functions
+//============================================================================//
+//============================================================================//
+
 public:
 
-  TinyGsm(Stream& stream)
+#ifdef GSM_DEFAULT_STREAM
+  TinyGsmA6(Stream& stream = GSM_DEFAULT_STREAM)
+#else
+  TinyGsmA6(Stream& stream)
+#endif
     : stream(stream)
   {
     memset(sockets, 0, sizeof(sockets));
@@ -209,8 +239,8 @@ public:
     for (unsigned long start = millis(); millis() - start < timeout; ) {
       sendAT(GF(""));
       if (waitResponse(200) == 1) {
-          delay(100);
-          return true;
+        delay(100);
+        return true;
       }
       delay(100);
     }
@@ -307,10 +337,10 @@ public:
       int status = waitResponse(GF("READY"), GF("SIM PIN"), GF("SIM PUK"));
       waitResponse();
       switch (status) {
-      case 2:
-      case 3:  return SIM_LOCKED;
-      case 1:  return SIM_READY;
-      default: return SIM_ERROR;
+        case 2:
+        case 3:  return SIM_LOCKED;
+        case 1:  return SIM_READY;
+        default: return SIM_ERROR;
       }
     }
     return SIM_ERROR;
@@ -370,6 +400,10 @@ public:
     return false;
   }
 
+  /*
+   * WiFi functions
+   */
+
   /*
    * GPRS functions
    */
@@ -650,9 +684,13 @@ public:
     streamWrite(tail...);
   }
 
-  bool streamSkipUntil(char c) { //TODO: timeout
-    while (true) {
-      while (!stream.available()) { TINY_GSM_YIELD(); }
+  bool streamSkipUntil(char c) {
+    const unsigned long timeout = 1000L;
+    unsigned long startMillis = millis();
+    while (millis() - startMillis < timeout) {
+      while (millis() - startMillis < timeout && !stream.available()) {
+        TINY_GSM_YIELD();
+      }
       if (stream.read() == c)
         return true;
     }
@@ -737,6 +775,7 @@ finish:
       }
       data = "";
     }
+    //DBG('<', index, '>');
     return index;
   }
 
diff --git a/src/TinyGsmClientBG96.h b/src/TinyGsmClientBG96.h
index f65da65..94e1643 100644
--- a/src/TinyGsmClientBG96.h
+++ b/src/TinyGsmClientBG96.h
@@ -16,7 +16,7 @@
   #define TINY_GSM_RX_BUFFER 64
 #endif
 
-#define TINY_GSM_MUX_COUNT 5
+#define TINY_GSM_MUX_COUNT 12
 
 #include <TinyGsmCommon.h>
 
@@ -39,10 +39,22 @@ enum RegStatus {
   REG_UNKNOWN      = 4,
 };
 
+//============================================================================//
+//============================================================================//
+//                    Declaration of the TinyGsmBG96 Class
+//============================================================================//
+//============================================================================//
 
 class TinyGsmBG96
 {
 
+//============================================================================//
+//============================================================================//
+//                         The Internal BG96 Client Class
+//============================================================================//
+//============================================================================//
+
+
 public:
 
 class GsmClient : public Client
@@ -173,6 +185,13 @@ private:
   RxFifo        rx;
 };
 
+//============================================================================//
+//============================================================================//
+//                          The BG96 Secure Client
+//============================================================================//
+//============================================================================//
+
+
 class GsmClientSecure : public GsmClient
 {
 public:
@@ -192,9 +211,19 @@ public:
   }
 };
 
+//============================================================================//
+//============================================================================//
+//                          The BG96 Modem Functions
+//============================================================================//
+//============================================================================//
+
 public:
 
+#ifdef GSM_DEFAULT_STREAM
+  TinyGsmBG96(Stream& stream = GSM_DEFAULT_STREAM)
+#else
   TinyGsmBG96(Stream& stream)
+#endif
     : stream(stream)
   {
     memset(sockets, 0, sizeof(sockets));
@@ -344,10 +373,10 @@ public:
       int status = waitResponse(GF("READY"), GF("SIM PIN"), GF("SIM PUK"), GF("NOT INSERTED"));
       waitResponse();
       switch (status) {
-      case 2:
-      case 3:  return SIM_LOCKED;
-      case 1:  return SIM_READY;
-      default: return SIM_ERROR;
+        case 2:
+        case 3:  return SIM_LOCKED;
+        case 1:  return SIM_READY;
+        default: return SIM_ERROR;
       }
     }
     return SIM_ERROR;
@@ -404,6 +433,10 @@ public:
     return false;
   }
 
+  /*
+   * WiFi functions
+   */
+
   /*
    * GPRS functions
    */
@@ -660,9 +693,13 @@ public:
     streamWrite(tail...);
   }
 
-  bool streamSkipUntil(char c) { //TODO: timeout
-    while (true) {
-      while (!stream.available()) { TINY_GSM_YIELD(); }
+  bool streamSkipUntil(char c) {
+    const unsigned long timeout = 1000L;
+    unsigned long startMillis = millis();
+    while (millis() - startMillis < timeout) {
+      while (millis() - startMillis < timeout && !stream.available()) {
+        TINY_GSM_YIELD();
+      }
       if (stream.read() == c)
         return true;
     }
@@ -743,6 +780,7 @@ finish:
       }
       data = "";
     }
+    //DBG('<', index, '>');
     return index;
   }
 
diff --git a/src/TinyGsmClientESP8266.h b/src/TinyGsmClientESP8266.h
index 44ed149..8777677 100644
--- a/src/TinyGsmClientESP8266.h
+++ b/src/TinyGsmClientESP8266.h
@@ -24,24 +24,51 @@ static const char GSM_OK[] TINY_GSM_PROGMEM = "OK" GSM_NL;
 static const char GSM_ERROR[] TINY_GSM_PROGMEM = "ERROR" GSM_NL;
 static unsigned TINY_GSM_TCP_KEEP_ALIVE = 120;
 
-class TinyGsm
+// <stat> status of ESP8266 station interface
+// 2 : ESP8266 station connected to an AP and has obtained IP
+// 3 : ESP8266 station created a TCP or UDP transmission
+// 4 : the TCP or UDP transmission of ESP8266 station disconnected
+// 5 : ESP8266 station did NOT connect to an AP
+enum RegStatus {
+  REG_OK_IP        = 2,
+  REG_OK_TCP       = 3,
+  REG_UNREGISTERED = 4,
+  REG_DENIED       = 5,
+  REG_UNKNOWN      = 6,
+};
+
+
+//============================================================================//
+//============================================================================//
+//                     Declaration of the TinyGsmESP8266 Class
+//============================================================================//
+//============================================================================//
+
+
+class TinyGsmESP8266
 {
 
+  //============================================================================//
+  //============================================================================//
+  //                      The ESP8266 Internal Client Class
+  //============================================================================//
+  //============================================================================//
+
 public:
 
 class GsmClient : public Client
 {
-  friend class TinyGsm;
+  friend class TinyGsmESP8266;
   typedef TinyGsmFifo<uint8_t, TINY_GSM_RX_BUFFER> RxFifo;
 
 public:
   GsmClient() {}
 
-  GsmClient(TinyGsm& modem, uint8_t mux = 1) {
+  GsmClient(TinyGsmESP8266& modem, uint8_t mux = 1) {
     init(&modem, mux);
   }
 
-  bool init(TinyGsm* modem, uint8_t mux = 1) {
+  bool init(TinyGsmESP8266* modem, uint8_t mux = 1) {
     this->at = modem;
     this->mux = mux;
     sock_connected = false;
@@ -144,18 +171,25 @@ public:
   String remoteIP() TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
 private:
-  TinyGsm*      at;
-  uint8_t       mux;
-  bool          sock_connected;
-  RxFifo        rx;
+  TinyGsmESP8266* at;
+  uint8_t         mux;
+  bool            sock_connected;
+  RxFifo          rx;
 };
 
+//============================================================================//
+//============================================================================//
+//                          The Secure ESP8266 Client Class
+//============================================================================//
+//============================================================================//
+
+
 class GsmClientSecure : public GsmClient
 {
 public:
   GsmClientSecure() {}
 
-  GsmClientSecure(TinyGsm& modem, uint8_t mux = 1)
+  GsmClientSecure(TinyGsmESP8266& modem, uint8_t mux = 1)
     : GsmClient(modem, mux)
   {}
 
@@ -169,9 +203,20 @@ public:
   }
 };
 
+
+//============================================================================//
+//============================================================================//
+//                          The ESP8266 Modem Functions
+//============================================================================//
+//============================================================================//
+
 public:
 
-  TinyGsm(Stream& stream)
+#ifdef GSM_DEFAULT_STREAM
+  TinyGsmESP8266(Stream& stream = GSM_DEFAULT_STREAM)
+#else
+  TinyGsmESP8266(Stream& stream)
+#endif
     : stream(stream)
   {
     memset(sockets, 0, sizeof(sockets));
@@ -192,6 +237,14 @@ public:
     if (waitResponse() != 1) {
       return false;
     }
+    sendAT(GF("+CIPMUX=1"));  // Enable Multiple Connections
+    if (waitResponse() != 1) {
+      return false;
+    }
+    sendAT(GF("+CWMODE_CUR=1"));  // Put into "station" mode
+    if (waitResponse() != 1) {
+      return false;
+    }
     return true;
   }
 
@@ -203,8 +256,8 @@ public:
     for (unsigned long start = millis(); millis() - start < timeout; ) {
       sendAT(GF(""));
       if (waitResponse(200) == 1) {
-          delay(100);
-          return true;
+        delay(100);
+        return true;
       }
       delay(100);
     }
@@ -255,6 +308,23 @@ public:
     return init();
   }
 
+  bool poweroff() TINY_GSM_ATTR_NOT_IMPLEMENTED;
+
+  bool radioOff() TINY_GSM_ATTR_NOT_IMPLEMENTED;
+
+  bool sleepEnable(bool enable = true) TINY_GSM_ATTR_NOT_IMPLEMENTED;
+
+  /*
+   * SIM card functions
+   */
+
+  RegStatus getRegistrationStatus() {
+    sendAT(GF("+CIPSTATUS"));
+    if (waitResponse(3000, GF("STATUS:")) != 1) return REG_UNKNOWN;
+    int status = waitResponse(GFP(GSM_ERROR), GF("2"), GF("3"), GF("4"), GF("5"));
+    waitResponse();  // Returns an OK after the status
+    return (RegStatus)status;
+  }
 
   /*
    * Generic network functions
@@ -275,21 +345,9 @@ public:
     return res2;
   }
 
-  bool isNetworkConnected() {
-    sendAT(GF("+CIPSTATUS"));
-    int res1 = waitResponse(3000, GF("STATUS:"));
-    int res2 = 0;
-    if (res1 == 1) {
-      res2 = waitResponse(GFP(GSM_ERROR), GF("2"), GF("3"), GF("4"), GF("5"));
-    }
-    // <stat> status of ESP8266 station interface
-    // 2 : ESP8266 station connected to an AP and has obtained IP
-    // 3 : ESP8266 station created a TCP or UDP transmission
-    // 4 : the TCP or UDP transmission of ESP8266 station disconnected (but AP is connected)
-    // 5 : ESP8266 station did NOT connect to an AP
-    waitResponse();  // Returns an OK after the status
-    if (res2 == 2 || res2 == 3 || res2 == 4) return true;
-    else return false;
+  bool isNetworkConnected()  {
+    RegStatus s = getRegistrationStatus();
+    return (s == REG_OK_IP || s == REG_OK_TCP);
   }
 
   bool waitForNetwork(unsigned long timeout = 60000L) {
@@ -298,7 +356,7 @@ public:
       int res1 = waitResponse(3000, GF("busy p..."), GF("STATUS:"));
       if (res1 == 2) {
         int res2 = waitResponse(GFP(GSM_ERROR), GF("2"), GF("3"), GF("4"), GF("5"));
-        if (res2 == 2 || res2 == 3 || res2 == 4) {
+        if (res2 == 2 || res2 == 3) {
             waitResponse();
             return true;
          }
@@ -312,17 +370,6 @@ public:
    * WiFi functions
    */
   bool networkConnect(const char* ssid, const char* pwd) {
-
-    sendAT(GF("+CIPMUX=1"));
-    if (waitResponse() != 1) {
-      return false;
-    }
-
-    sendAT(GF("+CWMODE_CUR=1"));
-    if (waitResponse() != 1) {
-      return false;
-    }
-
     sendAT(GF("+CWJAP_CUR=\""), ssid, GF("\",\""), pwd, GF("\""));
     if (waitResponse(30000L, GFP(GSM_OK), GF(GSM_NL "FAIL" GSM_NL)) != 1) {
       return false;
@@ -353,6 +400,28 @@ public:
     return TinyGsmIpFromString(getLocalIP());
   }
 
+  /*
+   * GPRS functions
+   */
+
+  /*
+   * Messaging functions
+   */
+
+  /*
+   * Location functions
+   */
+
+  String getGsmLocation() TINY_GSM_ATTR_NOT_AVAILABLE;
+
+  /*
+   * Battery functions
+   */
+
+  uint16_t getBattVoltage() TINY_GSM_ATTR_NOT_AVAILABLE;
+
+  int getBattPercent() TINY_GSM_ATTR_NOT_AVAILABLE;
+
 protected:
 
   bool modemConnect(const char* host, uint16_t port, uint8_t mux, bool ssl = false) {
@@ -384,21 +453,8 @@ protected:
   }
 
   bool modemGetConnected(uint8_t mux) {
-    // TODO: re-check this
-    sendAT(GF("+CIPSTATUS="), mux);
-    int res1 = waitResponse(3000, GF("STATUS:"));
-    int res2;
-    if (res1 == 1) {
-      res2 = waitResponse(GFP(GSM_ERROR), GF("2"), GF("3"), GF("4"), GF("5"));
-    }
-    // <stat> status of ESP8266 station interface
-    // 2 : ESP8266 station connected to an AP and has obtained IP
-    // 3 : ESP8266 station created a TCP or UDP transmission
-    // 4 : the TCP or UDP transmission of ESP8266 station disconnected (but AP is connected)
-    // 5 : ESP8266 station did NOT connect to an AP
-    waitResponse();  // Returns an OK after the status
-    if (res2 == 2 || res2 == 3 || res2 == 4) return true;
-    else return false;
+    RegStatus s = getRegistrationStatus();
+    return (s == REG_OK_IP || s == REG_OK_TCP);
   }
 
 public:
@@ -416,9 +472,13 @@ public:
     streamWrite(tail...);
   }
 
-  bool streamSkipUntil(char c) { //TODO: timeout
-    while (true) {
-      while (!stream.available()) { TINY_GSM_YIELD(); }
+  bool streamSkipUntil(char c) {
+    const unsigned long timeout = 1000L;
+    unsigned long startMillis = millis();
+    while (millis() - startMillis < timeout) {
+      while (millis() - startMillis < timeout && !stream.available()) {
+        TINY_GSM_YIELD();
+      }
       if (stream.read() == c)
         return true;
     }
@@ -505,6 +565,7 @@ finish:
       }
       data = "";
     }
+    //DBG('<', index, '>');
     return index;
   }
 
diff --git a/src/TinyGsmClientM590.h b/src/TinyGsmClientM590.h
index 21539ae..80252e7 100644
--- a/src/TinyGsmClientM590.h
+++ b/src/TinyGsmClientM590.h
@@ -39,24 +39,37 @@ enum RegStatus {
 };
 
 
-class TinyGsm
+//============================================================================//
+//============================================================================//
+//                    Declaration of the TinyGsmM590 Class
+//============================================================================//
+//============================================================================//
+
+class TinyGsmM590
 {
 
+//============================================================================//
+//============================================================================//
+//                          The M590 Internal Client Class
+//============================================================================//
+//============================================================================//
+
+
 public:
 
 class GsmClient : public Client
 {
-  friend class TinyGsm;
+  friend class TinyGsmM590;
   typedef TinyGsmFifo<uint8_t, TINY_GSM_RX_BUFFER> RxFifo;
 
 public:
   GsmClient() {}
 
-  GsmClient(TinyGsm& modem, uint8_t mux = 1) {
+  GsmClient(TinyGsmM590& modem, uint8_t mux = 1) {
     init(&modem, mux);
   }
 
-  bool init(TinyGsm* modem, uint8_t mux = 1) {
+  bool init(TinyGsmM590* modem, uint8_t mux = 1) {
     this->at = modem;
     this->mux = mux;
     sock_connected = false;
@@ -159,15 +172,33 @@ public:
   String remoteIP() TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
 private:
-  TinyGsm*      at;
+  TinyGsmM590*  at;
   uint8_t       mux;
   bool          sock_connected;
   RxFifo        rx;
 };
 
+//============================================================================//
+//============================================================================//
+//                          The M590 Has no Secure client!
+//============================================================================//
+//============================================================================//
+
+
+
+//============================================================================//
+//============================================================================//
+//                          The M590 Modem Functions
+//============================================================================//
+//============================================================================//
+
 public:
 
-  TinyGsm(Stream& stream)
+#ifdef GSM_DEFAULT_STREAM
+  TinyGsmM590(Stream& stream = GSM_DEFAULT_STREAM)
+#else
+  TinyGsmM590(Stream& stream)
+#endif
     : stream(stream)
   {
     memset(sockets, 0, sizeof(sockets));
@@ -205,8 +236,8 @@ public:
     for (unsigned long start = millis(); millis() - start < timeout; ) {
       sendAT(GF(""));
       if (waitResponse(200) == 1) {
-          delay(100);
-          return true;
+        delay(100);
+        return true;
       }
       delay(100);
     }
@@ -318,10 +349,10 @@ public:
       int status = waitResponse(GF("READY"), GF("SIM PIN"), GF("SIM PUK"));
       waitResponse();
       switch (status) {
-      case 2:
-      case 3:  return SIM_LOCKED;
-      case 1:  return SIM_READY;
-      default: return SIM_ERROR;
+        case 2:
+        case 3:  return SIM_LOCKED;
+        case 1:  return SIM_READY;
+        default: return SIM_ERROR;
       }
     }
     return SIM_ERROR;
@@ -378,6 +409,10 @@ public:
     return false;
   }
 
+  /*
+   * WiFi functions
+   */
+
   /*
    * GPRS functions
    */
@@ -408,12 +443,12 @@ public:
     }
     return false;
 
-set_dns:
-    sendAT(GF("+DNSSERVER=1,8.8.8.8"));
-    waitResponse();
-
-    sendAT(GF("+DNSSERVER=2,8.8.4.4"));
-    waitResponse();
+// set_dns:  // TODO
+//     sendAT(GF("+DNSSERVER=1,8.8.8.8"));
+//     waitResponse();
+//
+//     sendAT(GF("+DNSSERVER=2,8.8.4.4"));
+//     waitResponse();
 
     return true;
   }
@@ -595,9 +630,13 @@ public:
     streamWrite(tail...);
   }
 
-  bool streamSkipUntil(char c) { //TODO: timeout
-    while (true) {
-      while (!stream.available()) { TINY_GSM_YIELD(); }
+  bool streamSkipUntil(char c) {
+    const unsigned long timeout = 1000L;
+    unsigned long startMillis = millis();
+    while (millis() - startMillis < timeout) {
+      while (millis() - startMillis < timeout && !stream.available()) {
+        TINY_GSM_YIELD();
+      }
       if (stream.read() == c)
         return true;
     }
@@ -683,6 +722,7 @@ finish:
       }
       data = "";
     }
+    //DBG('<', index, '>');
     return index;
   }
 
diff --git a/src/TinyGsmClientSIM800.h b/src/TinyGsmClientSIM800.h
index a841a66..03b367c 100644
--- a/src/TinyGsmClientSIM800.h
+++ b/src/TinyGsmClientSIM800.h
@@ -39,15 +39,28 @@ enum RegStatus {
   REG_UNKNOWN      = 4,
 };
 
-enum DateTime {
+enum TinyGSMDateTimeFormat {
   DATE_FULL = 0,
   DATE_TIME = 1,
   DATE_DATE = 2
 };
 
+//============================================================================//
+//============================================================================//
+//                    Declaration of the TinyGsmSim800 Class
+//============================================================================//
+//============================================================================//
+
 class TinyGsmSim800
 {
 
+//============================================================================//
+//============================================================================//
+//                          The Sim800 Internal Client Class
+//============================================================================//
+//============================================================================//
+
+
 public:
 
 class GsmClient : public Client
@@ -179,14 +192,21 @@ public:
 
 private:
   TinyGsmSim800* at;
-  uint8_t       mux;
-  uint16_t      sock_available;
-  uint32_t      prev_check;
-  bool          sock_connected;
-  bool          got_data;
-  RxFifo        rx;
+  uint8_t        mux;
+  uint16_t       sock_available;
+  uint32_t       prev_check;
+  bool           sock_connected;
+  bool           got_data;
+  RxFifo         rx;
 };
 
+//============================================================================//
+//============================================================================//
+//                          The SIM800 Secure Client
+//============================================================================//
+//============================================================================//
+
+
 class GsmClientSecure : public GsmClient
 {
 public:
@@ -206,9 +226,19 @@ public:
   }
 };
 
+//============================================================================//
+//============================================================================//
+//                          The SIM800 Modem Functions
+//============================================================================//
+//============================================================================//
+
 public:
 
+#ifdef GSM_DEFAULT_STREAM
+  TinyGsmSim800(Stream& stream = GSM_DEFAULT_STREAM)
+#else
   TinyGsmSim800(Stream& stream)
+#endif
     : stream(stream)
   {
     memset(sockets, 0, sizeof(sockets));
@@ -244,8 +274,8 @@ public:
     for (unsigned long start = millis(); millis() - start < timeout; ) {
       sendAT(GF(""));
       if (waitResponse(200) == 1) {
-          delay(100);
-          return true;
+        delay(100);
+        return true;
       }
       delay(100);
     }
@@ -396,10 +426,10 @@ public:
       int status = waitResponse(GF("READY"), GF("SIM PIN"), GF("SIM PUK"), GF("NOT INSERTED"));
       waitResponse();
       switch (status) {
-      case 2:
-      case 3:  return SIM_LOCKED;
-      case 1:  return SIM_READY;
-      default: return SIM_ERROR;
+        case 2:
+        case 3:  return SIM_LOCKED;
+        case 1:  return SIM_READY;
+        default: return SIM_ERROR;
       }
     }
     return SIM_ERROR;
@@ -456,6 +486,10 @@ public:
     return false;
   }
 
+  /*
+   * WiFi functions
+   */
+
   /*
    * GPRS functions
    */
@@ -734,12 +768,12 @@ public:
   /*
    * Time functions
    */
-  String getGSMDateTime(DateTime format) {
+  String getGSMDateTime(TinyGSMDateTimeFormat format) {
     sendAT(GF("+CCLK?"));
     if (waitResponse(2000L, GF(GSM_NL "+CCLK: \"")) != 1) {
       return "";
     }
-    
+
     String res;
 
     switch(format) {
@@ -892,9 +926,13 @@ public:
     streamWrite(tail...);
   }
 
-  bool streamSkipUntil(char c) { //TODO: timeout
-    while (true) {
-      while (!stream.available()) { TINY_GSM_YIELD(); }
+  bool streamSkipUntil(char c) {
+    const unsigned long timeout = 1000L;
+    unsigned long startMillis = millis();
+    while (millis() - startMillis < timeout) {
+      while (millis() - startMillis < timeout && !stream.available()) {
+        TINY_GSM_YIELD();
+      }
       if (stream.read() == c)
         return true;
     }
@@ -975,6 +1013,7 @@ finish:
       }
       data = "";
     }
+    //DBG('<', index, '>');
     return index;
   }
 
diff --git a/src/TinyGsmClientSIM808.h b/src/TinyGsmClientSIM808.h
index 2b9c49a..b49ab85 100644
--- a/src/TinyGsmClientSIM808.h
+++ b/src/TinyGsmClientSIM808.h
@@ -11,6 +11,13 @@
 
 #include <TinyGsmClientSIM800.h>
 
+
+//============================================================================//
+//============================================================================//
+//              Declaration and Definitio of the TinyGsmSim808 Class
+//============================================================================//
+//============================================================================//
+
 class TinyGsmSim808: public TinyGsmSim800
 {
 
diff --git a/src/TinyGsmClientUBLOX.h b/src/TinyGsmClientUBLOX.h
index 9ea3c63..0117155 100644
--- a/src/TinyGsmClientUBLOX.h
+++ b/src/TinyGsmClientUBLOX.h
@@ -1,13 +1,13 @@
 /**
- * @file       TinyGsmClientU201.h
+ * @file       TinyGsmClientUBLOX.h
  * @author     Volodymyr Shymanskyy
  * @license    LGPL-3.0
  * @copyright  Copyright (c) 2016 Volodymyr Shymanskyy
  * @date       Nov 2016
  */
 
-#ifndef TinyGsmClientU201_h
-#define TinyGsmClientU201_h
+#ifndef TinyGsmClientUBLOX_h
+#define TinyGsmClientUBLOX_h
 
 //#define TINY_GSM_DEBUG Serial
 
@@ -39,31 +39,42 @@ enum RegStatus {
   REG_UNKNOWN      = 4,
 };
 
+//============================================================================//
+//============================================================================//
+//                   Declaration of the TinyGsmUBLOX Class
+//============================================================================//
+//============================================================================//
 
-class TinyGsmU201
+class TinyGsmUBLOX
 {
 
+//============================================================================//
+//============================================================================//
+//                          The UBLOX Internal Client Class
+//============================================================================//
+//============================================================================//
+
+
 public:
 
 class GsmClient : public Client
 {
-  friend class TinyGsmU201;
+  friend class TinyGsmUBLOX;
   typedef TinyGsmFifo<uint8_t, TINY_GSM_RX_BUFFER> RxFifo;
 
 public:
   GsmClient() {}
 
-  GsmClient(TinyGsmU201& modem, uint8_t mux = 1) {
+  GsmClient(TinyGsmUBLOX& modem, uint8_t mux = 1) {
     init(&modem, mux);
   }
 
-  bool init(TinyGsmU201* modem, uint8_t mux = 1) {
+  bool init(TinyGsmUBLOX* modem, uint8_t mux = 1) {
     this->at = modem;
     this->mux = mux;
     sock_available = 0;
     sock_connected = false;
     got_data = false;
-
     return true;
   }
 
@@ -109,7 +120,7 @@ public:
 
   virtual int available() {
     TINY_GSM_YIELD();
-    if (!rx.size()) {
+    if (!rx.size() && sock_connected) {
       at->maintain();
     }
     return rx.size() + sock_available;
@@ -164,7 +175,7 @@ public:
   String remoteIP() TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
 private:
-  TinyGsmU201*  at;
+  TinyGsmUBLOX* at;
   uint8_t       mux;
   uint16_t      sock_available;
   bool          sock_connected;
@@ -172,12 +183,19 @@ private:
   RxFifo        rx;
 };
 
+//============================================================================//
+//============================================================================//
+//                          The Secure UBLOX Client Class
+//============================================================================//
+//============================================================================//
+
+
 class GsmClientSecure : public GsmClient
 {
 public:
   GsmClientSecure() {}
 
-  GsmClientSecure(TinyGsmU201& modem, uint8_t mux = 1)
+  GsmClientSecure(TinyGsmUBLOX& modem, uint8_t mux = 1)
     : GsmClient(modem, mux)
   {}
 
@@ -192,12 +210,18 @@ public:
   }
 };
 
+//============================================================================//
+//============================================================================//
+//                          The UBLOX Modem Functions
+//============================================================================//
+//============================================================================//
+
 public:
 
 #ifdef GSM_DEFAULT_STREAM
-  TinyGsmU201(Stream& stream = GSM_DEFAULT_STREAM)
+  TinyGsmUBLOX(Stream& stream = GSM_DEFAULT_STREAM)
 #else
-  TinyGsmU201(Stream& stream)
+  TinyGsmUBLOX(Stream& stream)
 #endif
     : stream(stream)
   {
@@ -305,6 +329,8 @@ public:
     return true;
   }
 
+  bool sleepEnable(bool enable = true) TINY_GSM_ATTR_NOT_IMPLEMENTED;
+
   /*
    * SIM card functions
    */
@@ -346,10 +372,10 @@ public:
       int status = waitResponse(GF("READY"), GF("SIM PIN"), GF("SIM PUK"), GF("NOT INSERTED"));
       waitResponse();
       switch (status) {
-      case 2:
-      case 3:  return SIM_LOCKED;
-      case 1:  return SIM_READY;
-      default: return SIM_ERROR;
+        case 2:
+        case 3:  return SIM_LOCKED;
+        case 1:  return SIM_READY;
+        default: return SIM_ERROR;
       }
     }
     return SIM_ERROR;
@@ -406,6 +432,10 @@ public:
     return false;
   }
 
+  /*
+   * WiFi functions
+   */
+
   /*
    * GPRS functions
    */
@@ -507,7 +537,20 @@ public:
 
   String sendUSSD(const String& code) TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
-  bool sendSMS(const String& number, const String& text) TINY_GSM_ATTR_NOT_IMPLEMENTED;
+  bool sendSMS(const String& number, const String& text) {
+    sendAT(GF("+CSCS=\"GSM\""));  // Set GSM default alphabet
+    waitResponse();
+    sendAT(GF("+CMGF=1"));  // Set preferred message format to text mode
+    waitResponse();
+    sendAT(GF("+CMGS=\""), number, GF("\""));  // set the phone number
+    if (waitResponse(GF(">")) != 1) {
+      return false;
+    }
+    stream.print(text);  // Actually send the message
+    stream.write((char)0x1A);
+    stream.flush();
+    return waitResponse(60000L) == 1;
+  }
 
   bool sendSMS_UTF16(const String& number, const void* text, size_t len) TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
@@ -649,9 +692,13 @@ public:
     streamWrite(tail...);
   }
 
-  bool streamSkipUntil(char c) { //TODO: timeout
-    while (true) {
-      while (!stream.available()) { TINY_GSM_YIELD(); }
+  bool streamSkipUntil(char c) {
+    const unsigned long timeout = 1000L;
+    unsigned long startMillis = millis();
+    while (millis() - startMillis < timeout) {
+      while (millis() - startMillis < timeout && !stream.available()) {
+        TINY_GSM_YIELD();
+      }
       if (stream.read() == c)
         return true;
     }
@@ -727,6 +774,7 @@ finish:
       }
       data = "";
     }
+    //DBG('<', index, '>');
     return index;
   }
 
diff --git a/src/TinyGsmClientXBee.h b/src/TinyGsmClientXBee.h
index 87dbcda..67413a8 100644
--- a/src/TinyGsmClientXBee.h
+++ b/src/TinyGsmClientXBee.h
@@ -11,9 +11,6 @@
 
 //#define TINY_GSM_DEBUG Serial
 
-#if !defined(TINY_GSM_RX_BUFFER)
-  #define TINY_GSM_RX_BUFFER 256
-#endif
 
 #define TINY_GSM_MUX_COUNT 1  // Multi-plexing isn't supported using command mode
 
@@ -29,38 +26,54 @@ enum SimStatus {
   SIM_LOCKED = 2,
 };
 
-enum XBeeType {
-  S6B    = 0,
-  LTEC1  = 1,
-};
-
 enum RegStatus {
-  REG_UNREGISTERED = 0,
+  REG_OK           = 0,
+  REG_UNREGISTERED = 1,
   REG_SEARCHING    = 2,
   REG_DENIED       = 3,
-  REG_OK_HOME      = 1,
-  REG_OK_ROAMING   = 5,
   REG_UNKNOWN      = 4,
 };
 
+// These are responses to the HS command to get "hardware series"
+enum XBeeType {
+  XBEE_S6B_WIFI  = 0x601,  // Digi XBee® Wi-Fi
+  XBEE_LTE1_VZN  = 0xB01,  // Digi XBee® Cellular LTE Cat 1
+  XBEE_3G        = 0xB02,  // Digi XBee® Cellular 3G
+  XBEE3_LTE1_ATT = 1,  // Digi XBee3™ Cellular LTE CAT 1  -- HS unknown to SRGD
+  XBEE3_LTEM_ATT = 2,  // Digi XBee3™ Cellular LTE-M  -- HS unknown to SRGD
+  XBEE3_LTENB    = 3,  // Digi XBee3™ Cellular NB-IoT  -- HS unknown to SRGD
+};
+
+//============================================================================//
+//============================================================================//
+//                   Declaration of the TinyGsmXBee Class
+//============================================================================//
+//============================================================================//
 
-class TinyGsm
+class TinyGsmXBee
 {
 
+//============================================================================//
+//============================================================================//
+//                          The XBee Internal Client Class
+//============================================================================//
+//============================================================================//
+
+
 public:
 
 class GsmClient : public Client
 {
-  friend class TinyGsm;
+  friend class TinyGsmXBee;
 
 public:
   GsmClient() {}
 
-  GsmClient(TinyGsm& modem, uint8_t mux = 0) {
+  GsmClient(TinyGsmXBee& modem, uint8_t mux = 0) {
     init(&modem, mux);
   }
 
-  bool init(TinyGsm* modem, uint8_t mux = 0) {
+  bool init(TinyGsmXBee* modem, uint8_t mux = 0) {
     this->at = modem;
     this->mux = mux;
     sock_connected = false;
@@ -73,19 +86,25 @@ public:
 public:
   virtual int connect(const char *host, uint16_t port) {
     at->streamClear();  // Empty anything remaining in the buffer;
-    at->commandMode();
-    sock_connected = at->modemConnect(host, port, mux, false);
-    at->writeChanges();
-    at->exitCommand();
+    bool sock_connected = false;
+    if (at->commandMode())  {  // Don't try if we didn't successfully get into command mode
+      sock_connected = at->modemConnect(host, port, mux, false);
+      at->writeChanges();
+      at->exitCommand();
+    }
+    at->streamClear();  // Empty anything remaining in the buffer;
     return sock_connected;
   }
 
   virtual int connect(IPAddress ip, uint16_t port) {
     at->streamClear();  // Empty anything remaining in the buffer;
-    at->commandMode();
-    sock_connected = at->modemConnect(ip, port, mux, false);
-    at->writeChanges();
-    at->exitCommand();
+    bool sock_connected = false;
+    if (at->commandMode())  {  // Don't try if we didn't successfully get into command mode
+      sock_connected = at->modemConnect(ip, port, mux, false);
+      at->writeChanges();
+      at->exitCommand();
+    }
+    at->streamClear();  // Empty anything remaining in the buffer;
     return sock_connected;
   }
 
@@ -100,7 +119,7 @@ public:
     at->exitCommand();
     at->modemSend("", 1, mux);
     at->commandMode();
-    at->sendAT(GF("TM64"));  // Set socket timeout back to 10seconds;
+    at->sendAT(GF("TM64"));  // Set socket timeout back to 10 seconds;
     at->waitResponse();
     at->writeChanges();
     at->exitCommand();
@@ -110,7 +129,6 @@ public:
 
   virtual size_t write(const uint8_t *buf, size_t size) {
     TINY_GSM_YIELD();
-    //at->maintain();
     return at->modemSend(buf, size, mux);
   }
 
@@ -125,7 +143,7 @@ public:
 
   virtual int read(uint8_t *buf, size_t size) {
     TINY_GSM_YIELD();
-    return at->stream.readBytes(buf, size);
+    return at->stream.readBytes((char*)buf, size);
   }
 
   virtual int read() {
@@ -151,47 +169,69 @@ public:
   String remoteIP() TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
 private:
-  TinyGsm*      at;
+  TinyGsmXBee*  at;
   uint8_t       mux;
   bool          sock_connected;
 };
 
+//============================================================================//
+//============================================================================//
+//                          The Secure XBee Client Class
+//============================================================================//
+//============================================================================//
+
+
 class GsmClientSecure : public GsmClient
 {
 public:
   GsmClientSecure() {}
 
-  GsmClientSecure(TinyGsm& modem, uint8_t mux = 1)
+  GsmClientSecure(TinyGsmXBee& modem, uint8_t mux = 1)
     : GsmClient(modem, mux)
   {}
 
 public:
   virtual int connect(const char *host, uint16_t port) {
     at->streamClear();  // Empty anything remaining in the buffer;
-    at->commandMode();
-    sock_connected = at->modemConnect(host, port, mux, true);
-    at->writeChanges();
-    at->exitCommand();
+    bool sock_connected = false;
+    if (at->commandMode())  {  // Don't try if we didn't successfully get into command mode
+      sock_connected = at->modemConnect(host, port, mux, true);
+      at->writeChanges();
+      at->exitCommand();
+    }
+    at->streamClear();  // Empty anything remaining in the buffer;
     return sock_connected;
   }
 
   virtual int connect(IPAddress ip, uint16_t port) {
     at->streamClear();  // Empty anything remaining in the buffer;
-    at->commandMode();
-    sock_connected = at->modemConnect(ip, port, mux, true);
-    at->writeChanges();
-    at->exitCommand();
+    bool sock_connected = false;
+    if (at->commandMode())  {  // Don't try if we didn't successfully get into command mode
+      sock_connected = at->modemConnect(ip, port, mux, true);
+      at->writeChanges();
+      at->exitCommand();
+    }
+    at->streamClear();  // Empty anything remaining in the buffer;
     return sock_connected;
   }
 };
 
+
+//============================================================================//
+//============================================================================//
+//                          The XBee Modem Functions
+//============================================================================//
+//============================================================================//
+
 public:
 
-  TinyGsm(Stream& stream)
+#ifdef GSM_DEFAULT_STREAM
+  TinyGsmXBee(Stream& stream = GSM_DEFAULT_STREAM)
+#else
+  TinyGsmXBee(Stream& stream)
+#endif
     : stream(stream)
-  {
-    memset(sockets, 0, sizeof(sockets));
-  }
+  {}
 
   /*
    * Basic functions
@@ -201,23 +241,53 @@ public:
   }
 
   bool init() {
-    guardTime = 1100;
-    commandMode();
+    guardTime = 1100;  // Start with a default guard time of 1 second
+
+    if (!commandMode(10)) return false;  // Try up to 10 times for the init
+
     sendAT(GF("AP0"));  // Put in transparent mode
-    waitResponse();
+    bool ret_val = waitResponse() == 1;
+    ret_val &= writeChanges();
+
     sendAT(GF("GT64")); // shorten the guard time to 100ms
+    ret_val &= waitResponse();
+    ret_val &= writeChanges();
+    if (ret_val) guardTime = 125;
+
+    sendAT(GF("HS"));  // Get the "Hardware Series";
+    String res = readResponse();
+    char buf[4] = {0,};  // Set up buffer for response
+    res.toCharArray(buf, 4);
+    int intRes = strtol(buf, 0, 16);
+    beeType = (XBeeType)intRes;
+
+    exitCommand();
+    return ret_val;
+  }
+
+  void setBaud(unsigned long baud) {
+    if (!commandMode()) return;
+    switch(baud)
+    {
+      case 2400: sendAT(GF("BD1")); break;
+      case 4800: sendAT(GF("BD2")); break;
+      case 9600: sendAT(GF("BD3")); break;
+      case 19200: sendAT(GF("BD4")); break;
+      case 38400: sendAT(GF("BD5")); break;
+      case 57600: sendAT(GF("BD6")); break;
+      case 115200: sendAT(GF("BD7")); break;
+      case 230400: sendAT(GF("BD8")); break;
+      case 460800: sendAT(GF("BD9")); break;
+      case 921600: sendAT(GF("BDA")); break;
+      default: {
+          DBG(GF("Specified baud rate is unsupported! Setting to 9600 baud."));
+          sendAT(GF("BD3")); // Set to default of 9600
+          break;
+      }
+    }
     waitResponse();
     writeChanges();
-    sendAT(GF("HS"));  // Get the "Hardware Series"; 0x601 for S6B (Wifi)
-    // wait for the response
-    unsigned long startMillis = millis();
-    while (!stream.available() && millis() - startMillis < 1000) {};
-    String res = streamReadUntil('\r');  // Does not send an OK, just the result
     exitCommand();
-    if (res == "601") beeType = S6B;
-    else beeType = LTEC1;
-    guardTime = 125;
-    return true;
   }
 
   bool testAT(unsigned long timeout = 10000L) {
@@ -238,52 +308,100 @@ public:
   void maintain() {}
 
   bool factoryDefault() {
-    commandMode();
+    if (!commandMode()) return false;  // Return immediately
     sendAT(GF("RE"));
     bool ret_val = waitResponse() == 1;
-    writeChanges();
+    ret_val &= writeChanges();
     exitCommand();
     return ret_val;
   }
 
+  String getModemInfo() {
+    String modemInf = "";
+    if (!commandMode()) return modemInf;  // Try up to 10 times for the init
+
+    sendAT(GF("HS"));  // Get the "Hardware Series"
+    modemInf += readResponse();
+
+    exitCommand();
+    return modemInf;
+  }
+
   bool hasSSL() {
-    if (beeType == S6B) return false;
+    if (beeType == XBEE_S6B_WIFI) return false;
     else return true;
   }
 
+  XBeeType getBeeType() {
+    return beeType;
+  }
+
+  String getBeeName() {
+    switch (beeType){
+      case XBEE_S6B_WIFI: return "Digi XBee® Wi-Fi";
+      case XBEE_LTE1_VZN: return "Digi XBee® Cellular LTE Cat 1";
+      case XBEE_3G: return "Digi XBee® Cellular 3G";
+      case XBEE3_LTE1_ATT: return "Digi XBee3™ Cellular LTE CAT 1";
+      case XBEE3_LTEM_ATT: return "Digi XBee3™ Cellular LTE-M";
+      case XBEE3_LTENB: return "Digi XBee3™ Cellular NB-IoT";
+    }
+  }
+
   /*
    * Power functions
    */
 
   bool restart() {
-    commandMode();
+    if (!commandMode()) return false;  // Return immediately
+    sendAT(GF("AM1"));  // Digi suggests putting into airplane mode before restarting
+                       // This allows the sockets and connections to close cleanly
+    writeChanges();
+    if (waitResponse() != 1) goto fail;
     sendAT(GF("FR"));
-    if (waitResponse() != 1) {
-      return false;
-    }
+    if (waitResponse() != 1) goto fail;
+
     delay (2000);  // Actually resets about 2 seconds later
+
+    // Wait until reboot complete and responds to command mode call again
     for (unsigned long start = millis(); millis() - start < 60000L; ) {
-      if (commandMode()) {
+      if (commandMode(1)) {
+        sendAT(GF("AM0"));  // Turn off airplane mode
+        writeChanges();
         exitCommand();
-        return true;
+        delay(250);  // wait a litle before trying again
       }
     }
-    exitCommand();
-    return false;;
+    return true;
+
+
+    fail:
+      exitCommand();
+      return false;
   }
 
-  void setupPinSleep() {
-    commandMode();
-    sendAT(GF("SM"),1);
+  void setupPinSleep(bool maintainAssociation = false) {
+    if (!commandMode()) return;  // Return immediately
+    sendAT(GF("SM"),1);  // Pin sleep
     waitResponse();
-    if (beeType == S6B) {
-        sendAT(GF("SO"),200);
+    if (beeType == XBEE_S6B_WIFI && !maintainAssociation) {
+        sendAT(GF("SO"),200);  // For lowest power, dissassociated deep sleep
+        waitResponse();
+    }
+    else if (!maintainAssociation){
+        sendAT(GF("SO"),1);  // For lowest power, dissassociated deep sleep
+                             // Not supported by all modules, will return "ERROR"
         waitResponse();
     }
     writeChanges();
     exitCommand();
   }
 
+  bool poweroff() TINY_GSM_ATTR_NOT_IMPLEMENTED;
+
+  bool radioOff() TINY_GSM_ATTR_NOT_IMPLEMENTED;
+
+  bool sleepEnable(bool enable = true) TINY_GSM_ATTR_NOT_IMPLEMENTED;
+
   /*
    * SIM card functions
    */
@@ -293,23 +411,17 @@ public:
   }
 
   String getSimCCID() {
-    commandMode();
+    if (!commandMode()) return "";  // Return immediately
     sendAT(GF("S#"));
-    // wait for the response
-    unsigned long startMillis = millis();
-    while (!stream.available() && millis() - startMillis < 1000) {};
-    String res = streamReadUntil('\r');  // Does not send an OK, just the result
+    String res = readResponse();
     exitCommand();
     return res;
   }
 
   String getIMEI() {
-    commandMode();
+    if (!commandMode()) return "";  // Return immediately
     sendAT(GF("IM"));
-    // wait for the response
-    unsigned long startMillis = millis();
-    while (!stream.available() && millis() - startMillis < 1000) {};
-    String res = streamReadUntil('\r');  // Does not send an OK, just the result
+    String res = readResponse();
     exitCommand();
     return res;
   }
@@ -319,37 +431,82 @@ public:
   }
 
   RegStatus getRegistrationStatus() {
-    commandMode();
-    sendAT(GF("AI"));
-    // wait for the response
-    unsigned long startMillis = millis();
-    while (!stream.available() && millis() - startMillis < 1000) {};
-    String res = streamReadUntil('\r');  // Does not send an OK, just the result
-    exitCommand();
-
-    if(res == GF("0"))
-      return REG_OK_HOME;
+    if (!commandMode()) return REG_UNKNOWN;  // Return immediately
 
-    else if(res == GF("13") || res == GF("2A"))
-      return REG_UNREGISTERED;
-
-    else if(res == GF("FF") || res == GF("22") || res == GF("23") ||
-            res == GF("40") || res == GF("41") || res == GF("42"))
-      return REG_SEARCHING;
-
-    else if(res == GF("24") || res == GF("25") || res == GF("27"))
-      return REG_DENIED;
+    sendAT(GF("AI"));
+    String res = readResponse();
+    char buf[3] = {0,};  // Set up buffer for response
+    res.toCharArray(buf, 3);
+    int intRes = strtol(buf, 0, 16);
+    RegStatus stat = REG_UNKNOWN;
+
+    switch (beeType){
+      case XBEE_S6B_WIFI: {
+        if(intRes == 0x00)  // 0x00 Successfully joined an access point, established IP addresses and IP listening sockets
+          stat = REG_OK;
+        else if(intRes == 0x01)  // 0x01 Wi-Fi transceiver initialization in progress.
+          stat = REG_SEARCHING;
+        else if(intRes == 0x02)  // 0x02 Wi-Fi transceiver initialized, but not yet scanning for access point.
+          stat = REG_SEARCHING;
+        else if(intRes == 0x13) { // 0x13 Disconnecting from access point.
+          restart();  // Restart the device; the S6B tends to get stuck "disconnecting"
+          stat = REG_UNREGISTERED;
+        }
+        else if(intRes == 0x23)  // 0x23 SSID not configured.
+          stat = REG_UNREGISTERED;
+        else if(intRes == 0x24)  // 0x24 Encryption key invalid (either NULL or invalid length for WEP).
+          stat = REG_DENIED;
+        else if(intRes == 0x27)  // 0x27 SSID was found, but join failed.
+          stat = REG_DENIED;
+        else if(intRes == 0x40)  // 0x40 Waiting for WPA or WPA2 Authentication.
+          stat = REG_SEARCHING;
+        else if(intRes == 0x41)  // 0x41 Device joined a network and is waiting for IP configuration to complete
+          stat = REG_SEARCHING;
+        else if(intRes == 0x42)  // 0x42 Device is joined, IP is configured, and listening sockets are being set up.
+          stat = REG_SEARCHING;
+        else if(intRes == 0xFF)  // 0xFF Device is currently scanning for the configured SSID.
+          stat = REG_SEARCHING;
+        else stat = REG_UNKNOWN;
+        break;
+      }
+      default: {
+        if(intRes == 0x00)  // 0x00 Connected to the Internet.
+          stat = REG_OK;
+        else if(intRes == 0x22)  // 0x22 Registering to cellular network.
+          stat = REG_SEARCHING;
+        else if(intRes == 0x23)  // 0x23 Connecting to the Internet.
+          stat = REG_SEARCHING;
+        else if(intRes == 0x24)  // 0x24 The cellular component is missing, corrupt, or otherwise in error.
+          stat = REG_UNKNOWN;
+        else if(intRes == 0x25)  // 0x25 Cellular network registration denied.
+          stat = REG_DENIED;
+        else if(intRes == 0x2A) {  // 0x2A Airplane mode.
+          sendAT(GF("AM0"));  // Turn off airplane mode
+          waitResponse();
+          writeChanges();
+          stat = REG_UNKNOWN;
+        }
+        else if(intRes == 0x2F) {  // 0x2F Bypass mode active.
+          sendAT(GF("AP0"));  // Set back to transparent mode
+          waitResponse();
+          writeChanges();
+          stat = REG_UNKNOWN;
+        }
+        else if(intRes == 0xFF)  // 0xFF Device is currently scanning for the configured SSID.
+          stat = REG_SEARCHING;
+        else stat = REG_UNKNOWN;
+          break;
+        }
+    }
 
-    else return REG_UNKNOWN;
+    exitCommand();
+    return stat;
   }
 
   String getOperator() {
-    commandMode();
+    if (!commandMode()) return "";  // Return immediately
     sendAT(GF("MN"));
-    // wait for the response
-    unsigned long startMillis = millis();
-    while (!stream.available() && millis() - startMillis < 1000) {};
-    String res = streamReadUntil('\r');  // Does not send an OK, just the result
+    String res = readResponse();
     exitCommand();
     return res;
   }
@@ -359,25 +516,21 @@ public:
   */
 
   int getSignalQuality() {
-    commandMode();
-    if (beeType == S6B) sendAT(GF("LM"));  // ask for the "link margin" - the dB above sensitivity
+    if (!commandMode()) return 0;  // Return immediately
+    if (beeType == XBEE_S6B_WIFI) sendAT(GF("LM"));  // ask for the "link margin" - the dB above sensitivity
     else sendAT(GF("DB"));  // ask for the cell strength in dBm
-    // wait for the response
-    unsigned long startMillis = millis();
-    while (!stream.available() && millis() - startMillis < 1000) {};
-    char buf[2] = {0};  // Set up buffer for response
-    buf[0] = streamRead();
-    buf[1] = streamRead();
-    // DBG(buf[0], buf[1], "\n");
+    String res = readResponse();  // it works better if we read in as a string
     exitCommand();
-    int intr = strtol(buf, 0, 16);
-    if (beeType == S6B) return -93 + intr;  // the maximum sensitivity is -93dBm
-    else return -1*intr; // need to convert to negative number
+    char buf[3] = {0,};  // Set up buffer for response
+    res.toCharArray(buf, 3);
+    int intRes = strtol(buf, 0, 16);
+    if (beeType == XBEE_S6B_WIFI) return -93 + intRes;  // the maximum sensitivity is -93dBm
+    else return -1*intRes; // need to convert to negative number
   }
 
   bool isNetworkConnected() {
     RegStatus s = getRegistrationStatus();
-    return (s == REG_OK_HOME || s == REG_OK_ROAMING);
+    return (s == REG_OK);
   }
 
   bool waitForNetwork(unsigned long timeout = 60000L) {
@@ -385,7 +538,7 @@ public:
       if (isNetworkConnected()) {
         return true;
       }
-      delay(250);
+      // delay(250);  // Enough delay going in and out of command mode
     }
     return false;
   }
@@ -395,20 +548,16 @@ public:
    */
   bool networkConnect(const char* ssid, const char* pwd) {
 
-    commandMode();
+    if (!commandMode()) return false;  // return immediately
 
     sendAT(GF("EE"), 2);  // Set security to WPA2
-    waitResponse();
+    if (waitResponse() != 1) goto fail;
 
     sendAT(GF("ID"), ssid);
-    if (waitResponse() != 1) {
-      goto fail;
-    }
+    if (waitResponse() != 1) goto fail;
 
     sendAT(GF("PK"), pwd);
-    if (waitResponse() != 1) {
-      goto fail;
-    }
+    if (waitResponse() != 1) goto fail;
 
     writeChanges();
     exitCommand();
@@ -421,17 +570,22 @@ fail:
   }
 
   bool networkDisconnect() {
-    return false;  // Doesn't support disconnecting
+    if (!commandMode()) return false;  // return immediately
+    sendAT(GF("NR0"));  // Do a network reset in order to disconnect
+    int res = (1 == waitResponse(5000));
+    writeChanges();
+    exitCommand();
+    return res;
   }
 
   String getLocalIP() {
-    commandMode();
+    if (!commandMode()) return "";  // Return immediately
     sendAT(GF("MY"));
     String IPaddr; IPaddr.reserve(16);
-    // wait for the response
-    unsigned long startMillis = millis();
-    while (stream.available() < 8 && millis() - startMillis < 30000) {};
-    IPaddr = streamReadUntil('\r');  // read result
+    // wait for the response - this response can be very slow
+    IPaddr = readResponse(30000);
+    exitCommand();
+    IPaddr.trim();
     return IPaddr;
   }
 
@@ -443,7 +597,7 @@ fail:
    * GPRS functions
    */
   bool gprsConnect(const char* apn, const char* user = NULL, const char* pwd = NULL) {
-    commandMode();
+    if (!commandMode()) return false;  // Return immediately
     sendAT(GF("AN"), apn);  // Set the APN
     waitResponse();
     writeChanges();
@@ -451,8 +605,20 @@ fail:
     return true;
   }
 
-  bool gprsDisconnect() {  // TODO
-    return false;
+  bool gprsDisconnect() {
+    if (!commandMode()) return false;  // return immediately
+    sendAT(GF("AM1"));  // Cheating and disconnecting by turning on airplane mode
+    int res = (1 == waitResponse(5000));
+    writeChanges();
+    sendAT(GF("AM0"));  // Airplane mode off
+    waitResponse(5000);
+    writeChanges();
+    exitCommand();
+    return res;
+  }
+
+  bool isGprsConnected() {
+    return isNetworkConnected();
   }
 
   /*
@@ -462,35 +628,67 @@ fail:
   String sendUSSD(const String& code) TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
   bool sendSMS(const String& number, const String& text) {
-    commandMode();
+    if (!commandMode()) return false;  // Return immediately
+
     sendAT(GF("IP"), 2);  // Put in text messaging mode
-    waitResponse();
+    if (waitResponse() !=1) goto fail;
     sendAT(GF("PH"), number);  // Set the phone number
-    waitResponse();
-    sendAT(GF("TDD"));  // Set the text delimiter to the standard 0x0D (carriabe return)
-    waitResponse();
-    writeChanges();
+    if (waitResponse() !=1) goto fail;
+    sendAT(GF("TDD"));  // Set the text delimiter to the standard 0x0D (carriage return)
+    if (waitResponse() !=1) goto fail;
+    if (!writeChanges()) goto fail;
+
     exitCommand();
-    stream.print(text);
+    streamWrite(text);
     stream.write((char)0x0D);  // close off with the carriage return
     return true;
+
+    fail:
+      exitCommand();
+      return false;
   }
 
+  /*
+   * Location functions
+   */
 
-private:
+  String getGsmLocation() TINY_GSM_ATTR_NOT_AVAILABLE;
 
-  int modemConnect(const char* host, uint16_t port, uint8_t mux = 0, bool ssl = false) {
-    sendAT(GF("LA"), host);
+  /*
+   * Battery functions
+   */
+
+  uint16_t getBattVoltage() TINY_GSM_ATTR_NOT_AVAILABLE;
+
+  int getBattPercent() TINY_GSM_ATTR_NOT_AVAILABLE;
+
+protected:
+
+  bool modemConnect(const char* host, uint16_t port, uint8_t mux = 0, bool ssl = false) {
     String strIP; strIP.reserve(16);
-    // wait for the response
     unsigned long startMillis = millis();
-    while (stream.available() < 8 && millis() - startMillis < 30000) {};
-    strIP = streamReadUntil('\r');  // read result
-    IPAddress ip = TinyGsmIpFromString(strIP);
-    return modemConnect(ip, port, mux, ssl);
+    bool gotIP = false;
+    // XBee's require a numeric IP address for connection, but do provide the
+    // functionality to look up the IP address from a fully qualified domain name
+    while (!gotIP && millis() - startMillis < 45000L)  // the lookup can take a while
+    {
+      sendAT(GF("LA"), host);
+      while (stream.available() < 4) {};  // wait for any response
+      strIP = stream.readStringUntil('\r');  // read result
+      strIP.trim();
+      DBG("<<< ", strIP);
+      if (!strIP.endsWith(GF("ERROR"))) gotIP = true;
+      delay(100);  // short wait before trying again
+    }
+    if (gotIP) {  // No reason to continue if we don't know the IP address
+      IPAddress ip = TinyGsmIpFromString(strIP);
+      return modemConnect(ip, port, mux, ssl);
+    }
+    else return false;
   }
 
-  int modemConnect(IPAddress ip, uint16_t port, uint8_t mux = 0, bool ssl = false) {
+  bool modemConnect(IPAddress ip, uint16_t port, uint8_t mux = 0, bool ssl = false) {
+    bool success = true;
     String host; host.reserve(16);
     host += ip[0];
     host += ".";
@@ -500,17 +698,17 @@ private:
     host += ".";
     host += ip[3];
     if (ssl) {
-      sendAT(GF("IP"), 4);  // Put in TCP mode
-      waitResponse();
+      sendAT(GF("IP"), 4);  // Put in SSL over TCP communication mode
+      success &= (1 == waitResponse());
     } else {
       sendAT(GF("IP"), 1);  // Put in TCP mode
-      waitResponse();
+      success &= (1 == waitResponse());
     }
     sendAT(GF("DL"), host);  // Set the "Destination Address Low"
-    waitResponse();
+    success &= (1 == waitResponse());
     sendAT(GF("DE"), String(port, HEX));  // Set the destination port
-    int rsp = waitResponse();
-    return rsp;
+    success &= (1 == waitResponse());
+    return success;
   }
 
   int modemSend(const void* buff, size_t len, uint8_t mux = 0) {
@@ -520,7 +718,7 @@ private:
   }
 
   bool modemGetConnected(uint8_t mux = 0) {
-    commandMode();
+    if (!commandMode()) return false;
     sendAT(GF("AI"));
     int res = waitResponse(GF("0"));
     exitCommand();
@@ -542,32 +740,33 @@ public:
     streamWrite(tail...);
   }
 
-  int streamRead() { return stream.read(); }
-
-  String streamReadUntil(char c) {
-    TINY_GSM_YIELD();
-    String return_string = stream.readStringUntil(c);
-    return_string.trim();
-    // DBG(return_string, c);
-    return return_string;
-  }
-
   void streamClear(void) {
-    while (stream.available()) { streamRead(); }
-  }
-
-  bool commandMode(void) {
-    delay(guardTime);  // cannot send anything for 1 second before entering command mode
-    streamWrite(GF("+++"));  // enter command mode
-    // DBG("\r\n+++\r\n");
-    return 1 == waitResponse(guardTime*2);
+    TINY_GSM_YIELD();
+    while (stream.available()) { stream.read(); }
+  }
+
+  bool commandMode(int retries = 2) {
+    int triesMade = 0;
+    bool success = false;
+    streamClear();  // Empty everything in the buffer before starting
+    while (!success and triesMade < retries) {
+      // Cannot send anything for 1 "guard time" before entering command mode
+      // Default guard time is 1s, but the init fxn decreases it to 250 ms
+      delay(guardTime);
+      streamWrite(GF("+++"));  // enter command mode
+      DBG("+++");
+      success = (1 == waitResponse(guardTime*2));
+      triesMade ++;
+    }
+    return success;
   }
 
-  void writeChanges(void) {
+  bool writeChanges(void) {
     sendAT(GF("WR"));  // Write changes to flash
-    waitResponse();
+    if (1 != waitResponse()) return false;
     sendAT(GF("AC"));  // Apply changes
-    waitResponse();
+    if (1 != waitResponse()) return false;
+    return true;
   }
 
   void exitCommand(void) {
@@ -575,6 +774,16 @@ public:
     waitResponse();
   }
 
+  String readResponse(uint32_t timeout = 1000) {
+    TINY_GSM_YIELD();
+    unsigned long startMillis = millis();
+    while (!stream.available() && millis() - startMillis < timeout) {};
+    String res = stream.readStringUntil('\r');  // lines end with carriage returns
+    res.trim();
+    DBG("<<< ", res);
+    return res;
+  }
+
   template<typename... Args>
   void sendAT(Args... cmd) {
     streamWrite("AT", cmd..., GSM_NL);
@@ -594,13 +803,13 @@ public:
     String r4s(r4); r4s.trim();
     String r5s(r5); r5s.trim();
     DBG("### ..:", r1s, ",", r2s, ",", r3s, ",", r4s, ",", r5s);*/
-    data.reserve(64);
+    data.reserve(16);  // Should never be getting much here for the XBee
     int index = 0;
     unsigned long startMillis = millis();
     do {
       TINY_GSM_YIELD();
       while (stream.available() > 0) {
-        int a = streamRead();
+        int a = stream.read();
         if (a <= 0) continue; // Skip 0x00 bytes, just in case
         data += (char)a;
         if (r1 && data.endsWith(r1)) {
@@ -625,7 +834,7 @@ finish:
     if (!index) {
       data.trim();
       data.replace(GSM_NL GSM_NL, GSM_NL);
-      data.replace(GSM_NL, "\r\n" "    ");
+      data.replace(GSM_NL, "\r\n    ");
       if (data.length()) {
         DBG("### Unhandled:", data, "\r\n");
       } else {