Merge pull request #276 from EnviroDIY/master

Fix for #266

library.json

@@ -1,6 +1,6 @@
 {
   "name": "TinyGSM",
-  "version": "0.6.1",
+  "version": "0.6.2",
   "description": "A small Arduino library for GPRS modules, that just works. Includes examples for Blynk, MQTT, File Download, and Web Client. Supports many GSM, LTE, and WiFi modules with AT command interfaces.",
   "keywords": "GSM, AT commands, AT, SIM800, SIM900, A6, A7, M590, ESP8266, SIM7000, SIM800A, SIM800C, SIM800L, SIM800H, SIM808, SIM868, SIM900A, SIM900D, SIM908, SIM968, M95, MC60, MC60E, BG96, ublox, Quectel, SIMCOM, AI Thinker, LTE, LTE-M",
   "authors":

library.properties

@@ -1,5 +1,5 @@
 name=TinyGSM
-version=0.6.1
+version=0.6.2
 author=Volodymyr Shymanskyy
 maintainer=Volodymyr Shymanskyy
 sentence=A small Arduino library for GPRS modules, that just works.

src/TinyGsmClientA6.h

@@ -58,6 +58,10 @@ public:
     this->mux = -1;
     sock_connected = false;
 
+    // at->sockets[mux] = this;
+    //  ^^ TODO: attach the socket here at init?  Or later at connect?
+    // Currently done inconsistently between modems
+
     return true;
   }
 
@@ -71,6 +75,8 @@ public:
     if (sock_connected) {
       mux = newMux;
       at->sockets[mux] = this;
+    // ^^ TODO: attach the socet after attempting connection or above at init?
+    // Currently done inconsistently between modems
     }
     return sock_connected;
   }
@@ -112,7 +118,7 @@ public:
 
   virtual int available() {
     TINY_GSM_YIELD();
-    if (!rx.size()) {
+    if (!rx.size() && sock_connected) {
       at->maintain();
     }
     return rx.size();

src/TinyGsmClientBG96.h

@@ -62,6 +62,8 @@ public:
     got_data = false;
 
     at->sockets[mux] = this;
+    //  ^^ TODO: attach the socket here at init?  Or later at connect?
+    // Currently done inconsistently between modems
 
     return true;
   }
@@ -72,6 +74,10 @@ public:
     TINY_GSM_YIELD();
     rx.clear();
     sock_connected = at->modemConnect(host, port, mux);
+    // sock_connected = at->modemConnect(host, port, &mux);
+    // at->sockets[mux] = this;
+    // ^^ TODO: attach the socet after attempting connection or above at init?
+    // Currently done inconsistently between modems
     return sock_connected;
   }
 
@@ -97,7 +103,7 @@ public:
     rx.clear();
     at->maintain();
     while (sock_available > 0) {
-      sock_available -= at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
+      at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
       rx.clear();
       at->maintain();
     }
@@ -144,7 +150,7 @@ public:
       // TODO: Read directly into user buffer?
       at->maintain();
       if (sock_available > 0) {
-        sock_available -= at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
+        at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
       } else {
         break;
       }
@@ -178,12 +184,12 @@ public:
   String remoteIP() TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
 private:
-  TinyGsmBG96*  at;
-  uint8_t       mux;
-  uint16_t      sock_available;
-  bool          sock_connected;
-  bool          got_data;
-  RxFifo        rx;
+  TinyGsmBG96*   at;
+  uint8_t         mux;
+  uint16_t        sock_available;
+  bool            sock_connected;
+  bool            got_data;
+  RxFifo          rx;
 };
 
 
@@ -632,6 +638,7 @@ protected:
       return 0;
     }
     // TODO: Wait for ACK? AT+QISEND=id,0
+    maintain();  // look for a very quick response from the remote
     return len;
   }
 
@@ -641,6 +648,7 @@ protected:
       return 0;
     }
     size_t len = stream.readStringUntil('\n').toInt();
+    sockets[mux]->sock_available = len;
 
     for (size_t i=0; i<len; i++) {
       while (!stream.available()) { TINY_GSM_YIELD(); }
@@ -648,7 +656,8 @@ protected:
       sockets[mux]->rx.put(c);
     }
     waitResponse();
-    DBG("### READ:", mux, ",", len);
+    DBG("### READ:", len, "from", mux);
+    maintain();  // Listen for a close or other URC
     return len;
   }
 
@@ -659,12 +668,13 @@ protected:
       streamSkipUntil(','); // Skip total received
       streamSkipUntil(','); // Skip have read
       result = stream.readStringUntil('\n').toInt();
-      DBG("### STILL:", mux, "has", result);
+      DBG("### DATA AVAILABLE:", result, "on", mux);
       waitResponse();
     }
     if (!result) {
       sockets[mux]->sock_connected = modemGetConnected(mux);
     }
+    maintain();  // Listen for a close or other URC
     return result;
   }
 
@@ -683,6 +693,7 @@ protected:
     int res = stream.readStringUntil(',').toInt(); // socket state
 
     waitResponse();
+    maintain();  // Listen for a close or other URC
 
     // 0 Initial, 1 Opening, 2 Connected, 3 Listening, 4 Closing
     return 2 == res;

src/TinyGsmClientESP8266.h

@@ -59,6 +59,8 @@ public:
     sock_connected = false;
 
     at->sockets[mux] = this;
+    //  ^^ TODO: attach the socket here at init?  Or later at connect?
+    // Currently done inconsistently between modems
 
     return true;
   }
@@ -69,6 +71,10 @@ public:
     TINY_GSM_YIELD();
     rx.clear();
     sock_connected = at->modemConnect(host, port, mux);
+    // sock_connected = at->modemConnect(host, port, &mux);
+    // at->sockets[mux] = this;
+    // ^^ TODO: attach the socet after attempting connection or above at init?
+    // Currently done inconsistently between modems
     return sock_connected;
   }
 
@@ -109,7 +115,7 @@ public:
 
   virtual int available() {
     TINY_GSM_YIELD();
-    if (!rx.size()) {
+    if (!rx.size() && sock_connected) {
       at->maintain();
     }
     return rx.size();
@@ -183,6 +189,10 @@ public:
     TINY_GSM_YIELD();
     rx.clear();
     sock_connected = at->modemConnect(host, port, mux, true);
+    // sock_connected = at->modemConnect(host, port, &mux);
+    // at->sockets[mux] = this;
+    // ^^ TODO: attach the socet after attempting connection or above at init?
+    // Currently done inconsistently between modems
     return sock_connected;
   }
 };

src/TinyGsmClientM590.h

@@ -59,6 +59,8 @@ public:
     sock_connected = false;
 
     at->sockets[mux] = this;
+    //  ^^ TODO: attach the socket here at init?  Or later at connect?
+    // Currently done inconsistently between modems
 
     return true;
   }
@@ -69,6 +71,10 @@ public:
     TINY_GSM_YIELD();
     rx.clear();
     sock_connected = at->modemConnect(host, port, mux);
+    // sock_connected = at->modemConnect(host, port, &mux);
+    // at->sockets[mux] = this;
+    // ^^ TODO: attach the socet after attempting connection or above at init?
+    // Currently done inconsistently between modems
     return sock_connected;
   }
 
@@ -128,7 +134,7 @@ public:
         continue;
       }
       // TODO: Read directly into user buffer?
-      if (!rx.size()) {
+      if (!rx.size() && sock_connected) {
         at->maintain();
       }
     }
@@ -161,10 +167,10 @@ public:
   String remoteIP() TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
 private:
-  TinyGsmM590*  at;
-  uint8_t       mux;
-  bool          sock_connected;
-  RxFifo        rx;
+  TinyGsmM590*   at;
+  uint8_t         mux;
+  bool            sock_connected;
+  RxFifo          rx;
 };
 
 

src/TinyGsmClientM95.h

@@ -62,6 +62,8 @@ public:
     got_data = false;
 
     at->sockets[mux] = this;
+    //  ^^ TODO: attach the socket here at init?  Or later at connect?
+    // Currently done inconsistently between modems
 
     return true;
   }
@@ -72,6 +74,10 @@ public:
     TINY_GSM_YIELD();
     rx.clear();
     sock_connected = at->modemConnect(host, port, mux);
+    // sock_connected = at->modemConnect(host, port, &mux);
+    // at->sockets[mux] = this;
+    // ^^ TODO: attach the socet after attempting connection or above at init?
+    // Currently done inconsistently between modems
     return sock_connected;
   }
 
@@ -97,7 +103,7 @@ public:
     rx.clear();
     at->maintain();
     while (sock_available > 0) {
-      sock_available -= at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
+      at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
       rx.clear();
       at->maintain();
     }
@@ -144,7 +150,7 @@ public:
       // TODO: Read directly into user buffer?
       at->maintain();
       if (sock_available > 0) {
-        sock_available -= at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
+        at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
       } else {
         break;
       }
@@ -178,12 +184,12 @@ public:
   String remoteIP() TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
 private:
-  TinyGsmM95*   at;
-  uint8_t       mux;
-  uint16_t      sock_available;
-  bool          sock_connected;
-  bool          got_data;
-  RxFifo        rx;
+  TinyGsmM95*     at;
+  uint8_t         mux;
+  uint16_t        sock_available;
+  bool            sock_connected;
+  bool            got_data;
+  RxFifo          rx;
 };
 
 
@@ -684,10 +690,11 @@ protected:
       }
     }
     waitResponse(5000L);
+    maintain();  // look for a very quick response from the remote
 
     // streamSkipUntil(','); // Skip mux
     // return stream.readStringUntil('\n').toInt();
-    return 1;
+    return len;  // TODO
   }
 
   size_t modemRead(size_t size, uint8_t mux) {
@@ -696,6 +703,7 @@ protected:
       return 0;
     }
     size_t len = stream.readStringUntil('\n').toInt();
+    sockets[mux]->sock_available = len;
 
     for (size_t i=0; i<len; i++) {
       while (!stream.available()) { TINY_GSM_YIELD(); }
@@ -703,7 +711,8 @@ protected:
       sockets[mux]->rx.put(c);
     }
     waitResponse();
-    DBG("### READ:", mux, ",", len);
+    DBG("### READ:", len, "from", mux);
+    maintain();  // Listen for a close or other URC
     return len;
   }
 
@@ -714,12 +723,13 @@ protected:
       streamSkipUntil(','); // Skip total received
       streamSkipUntil(','); // Skip have read
       result = stream.readStringUntil('\n').toInt();
-      DBG("### STILL:", mux, "has", result);
+      DBG("### DATA AVAILABLE:", result, "on", mux);
       waitResponse();
     }
     if (!result) {
       sockets[mux]->sock_connected = modemGetConnected(mux);
     }
+    maintain();  // Listen for a close or other URC
     return result;
   }
 
@@ -738,6 +748,7 @@ protected:
     int res = stream.readStringUntil(',').toInt(); // socket state
 
     waitResponse();
+    maintain();  // Listen for a close or other URC
 
     // 0 Initial, 1 Opening, 2 Connected, 3 Listening, 4 Closing
     return 2 == res;

src/TinyGsmClientMC60.h

@@ -66,6 +66,8 @@ public:
     got_data = false;
 
     at->sockets[mux] = this;
+    //  ^^ TODO: attach the socket here at init?  Or later at connect?
+    // Currently done inconsistently between modems
 
     return true;
   }
@@ -76,6 +78,10 @@ public:
     TINY_GSM_YIELD();
     rx.clear();
     sock_connected = at->modemConnect(host, port, mux);
+    // sock_connected = at->modemConnect(host, port, &mux);
+    // at->sockets[mux] = this;
+    // ^^ TODO: attach the socet after attempting connection or above at init?
+    // Currently done inconsistently between modems
     return sock_connected;
   }
 
@@ -101,7 +107,7 @@ public:
     rx.clear();
     at->maintain();
     while (sock_available > 0) {
-      sock_available -= at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
+      at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
       rx.clear();
       at->maintain();
     }
@@ -148,7 +154,7 @@ public:
       // TODO: Read directly into user buffer?
       at->maintain();
       if (sock_available > 0) {
-        sock_available -= at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
+        at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
       } else {
         break;
       }
@@ -182,12 +188,12 @@ public:
   String remoteIP() TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
 private:
-  TinyGsmMC60*  at;
-  uint8_t       mux;
-  uint16_t      sock_available;
-  bool          sock_connected;
-  bool          got_data;
-  RxFifo        rx;
+  TinyGsmMC60*    at;
+  uint8_t         mux;
+  uint16_t        sock_available;
+  bool            sock_connected;
+  bool            got_data;
+  RxFifo          rx;
 };
 
 
@@ -715,7 +721,9 @@ protected:
 
     // streamSkipUntil(','); // Skip mux
     // return stream.readStringUntil('\n').toInt();
-    return 1;
+
+    maintain();  // look for a very quick response from the remote
+    return len;  // TODO
   }
 
   size_t modemRead(size_t size, uint8_t mux) {
@@ -724,6 +732,7 @@ protected:
       return 0;
     }
     size_t len = stream.readStringUntil('\n').toInt();
+    sockets[mux]->sock_available = len;
 
     for (size_t i=0; i<len; i++) {
       while (!stream.available()) { TINY_GSM_YIELD(); }
@@ -731,7 +740,8 @@ protected:
       sockets[mux]->rx.put(c);
     }
     waitResponse();
-    DBG("### READ:", mux, ",", len);
+    DBG("### READ:", len, "from", mux);
+    maintain();  // Listen for a close or other URC
     return len;
   }
 
@@ -742,12 +752,13 @@ protected:
       streamSkipUntil(','); // Skip total received
       streamSkipUntil(','); // Skip have read
       result = stream.readStringUntil('\n').toInt();
-      DBG("### STILL:", mux, "has", result);
+      DBG("### DATA AVAILABLE:", result, "on", mux);
       waitResponse();
     }
     if (!result) {
       sockets[mux]->sock_connected = modemGetConnected(mux);
     }
+    maintain();  // Listen for a close or other URC
     return result;
   }
 
@@ -766,6 +777,7 @@ protected:
     int res = stream.readStringUntil(',').toInt(); // socket state
 
     waitResponse();
+    maintain();  // Listen for a close or other URC
 
     // 0 Initial, 1 Opening, 2 Connected, 3 Listening, 4 Closing
     return 2 == res;

src/TinyGsmClientSIM7000.h

@@ -71,6 +71,8 @@ public:
     got_data = false;
 
     at->sockets[mux] = this;
+    //  ^^ TODO: attach the socket here at init?  Or later at connect?
+    // Currently done inconsistently between modems
 
     return true;
   }
@@ -81,6 +83,10 @@ public:
     TINY_GSM_YIELD();
     rx.clear();
     sock_connected = at->modemConnect(host, port, mux);
+    // sock_connected = at->modemConnect(host, port, &mux);
+    // at->sockets[mux] = this;
+    // ^^ TODO: attach the socet after attempting connection or above at init?
+    // Currently done inconsistently between modems
     return sock_connected;
   }
 
@@ -106,7 +112,7 @@ public:
     rx.clear();
     at->maintain();
     while (sock_available > 0) {
-      sock_available -= at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
+      at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
       rx.clear();
       at->maintain();
     }
@@ -166,10 +172,10 @@ public:
         got_data = true;
         prev_check = millis();
       }
-      at->maintain();
       // TODO: Read directly into user buffer?
+      at->maintain();
       if (sock_available > 0) {
-        sock_available -= at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
+        at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
       } else {
         break;
       }
@@ -204,12 +210,12 @@ public:
 
 private:
   TinyGsmSim7000* 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;
 };
 
 
@@ -228,6 +234,9 @@ public:
     TINY_GSM_YIELD();
     rx.clear();
     sock_connected = at->modemConnect(host, port, mux, true);
+    // sock_connected = at->modemConnect(host, port, &mux, true);
+    // at->sockets[mux] = this;
+    // TODO:  When is the socket attached?
     return sock_connected;
   }
 };
@@ -421,6 +430,7 @@ public:
 
   RegStatus getRegistrationStatus() {
     sendAT(GF("+CGREG?"));
+    // TODO:  Shouldn't this be CEREG for the EPS status of this 4G module?
     if (waitResponse(GF(GSM_NL "+CGREG:")) != 1) {
       return REG_UNKNOWN;
     }
@@ -932,6 +942,7 @@ protected:
       return 0;
     }
     streamSkipUntil(','); // Skip mux
+    maintain();  // look for a very quick response from the remote
     return stream.readStringUntil('\n').toInt();
   }
 
@@ -947,12 +958,19 @@ protected:
       return 0;
     }
 #endif
-    streamSkipUntil(','); // Skip mode 2/3
+    streamSkipUntil(','); // Skip Rx mode 2/normal or 3/HEX
     streamSkipUntil(','); // Skip mux
-    size_t len = stream.readStringUntil(',').toInt();
-    sockets[mux]->sock_available = stream.readStringUntil('\n').toInt();
+    size_t len_requested = stream.readStringUntil(',').toInt();
+    //  ^^ Requested number of data bytes (1-1460 bytes)to be read
+    size_t len_confirmed = stream.readStringUntil('\n').toInt();
+    if (len_confirmed > len_requested) {
+      DBG(len_requested - len_confirmed, "fewer bytes confirmed than requested!");
+    }
+    sockets[mux]->sock_available = len_confirmed;
+    // ^^ Confirmed number of data bytes to be read, which may be less than requested.
+    // 0 indicates that no data can be read.
 
-    for (size_t i=0; i<len; i++) {
+    for (size_t i=0; i<len_confirmed; i++) {
 #ifdef TINY_GSM_USE_HEX
       while (stream.available() < 2) { TINY_GSM_YIELD(); }
       char buf[4] = { 0, };
@@ -966,7 +984,9 @@ protected:
       sockets[mux]->rx.put(c);
     }
     waitResponse();
-    return len;
+    DBG("### READ:", len_confirmed, "from", mux);
+    maintain();  // Listen for a close or other URC
+    return len_confirmed;
   }
 
   size_t modemGetAvailable(uint8_t mux) {
@@ -981,6 +1001,7 @@ protected:
     if (!result) {
       sockets[mux]->sock_connected = modemGetConnected(mux);
     }
+    maintain();  // Listen for a close or other URC
     return result;
   }
 
@@ -988,6 +1009,7 @@ protected:
     sendAT(GF("+CIPSTATUS="), mux);
     int res = waitResponse(GF(",\"CONNECTED\""), GF(",\"CLOSED\""), GF(",\"CLOSING\""), GF(",\"INITIAL\""));
     waitResponse();
+    maintain();  // Listen for a close or other URC
     return 1 == res;
   }
 
@@ -1048,9 +1070,19 @@ public:
               sockets[mux]->got_data = true;
             }
             data = "";
+            DBG("### Got Data:", mux);
           } else {
             data += mode;
           }
+        } else if (data.endsWith(GF(GSM_NL "+RECEIVE:"))) {
+          int mux = stream.readStringUntil(',').toInt();
+          int len = stream.readStringUntil('\n').toInt();
+          if (mux >= 0 && mux < TINY_GSM_MUX_COUNT && sockets[mux]) {
+            sockets[mux]->got_data = true;
+            sockets[mux]->sock_available = len;
+          }
+          data = "";
+          DBG("### Got Data:", len, "on", mux);
         } else if (data.endsWith(GF("CLOSED" GSM_NL))) {
           int nl = data.lastIndexOf(GSM_NL, data.length()-8);
           int coma = data.indexOf(',', nl+2);

src/TinyGsmClientSIM800.h

@@ -68,6 +68,8 @@ public:
     got_data = false;
 
     at->sockets[mux] = this;
+    //  ^^ TODO: attach the socket here at init?  Or later at connect?
+    // Currently done inconsistently between modems
 
     return true;
   }
@@ -78,6 +80,10 @@ public:
     TINY_GSM_YIELD();
     rx.clear();
     sock_connected = at->modemConnect(host, port, mux);
+    // sock_connected = at->modemConnect(host, port, &mux);
+    // at->sockets[mux] = this;
+    // ^^ TODO: attach the socet after attempting connection or above at init?
+    // Currently done inconsistently between modems
     return sock_connected;
   }
 
@@ -103,7 +109,7 @@ public:
     rx.clear();
     at->maintain();
     while (sock_available > 0) {
-      sock_available -= at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
+      at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
       rx.clear();
       at->maintain();
     }
@@ -161,10 +167,10 @@ public:
         got_data = true;
         prev_check = millis();
       }
-      at->maintain();
       // TODO: Read directly into user buffer?
+      at->maintain();
       if (sock_available > 0) {
-        sock_available -= at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
+        at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
       } else {
         break;
       }
@@ -198,13 +204,13 @@ public:
   String remoteIP() TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
 private:
-  TinyGsmSim800* at;
-  uint8_t        mux;
-  uint16_t       sock_available;
-  uint32_t       prev_check;
-  bool           sock_connected;
-  bool           got_data;
-  RxFifo         rx;
+  TinyGsmSim800*  at;
+  uint8_t         mux;
+  uint16_t        sock_available;
+  uint32_t        prev_check;
+  bool            sock_connected;
+  bool            got_data;
+  RxFifo          rx;
 };
 
 
@@ -223,6 +229,9 @@ public:
     TINY_GSM_YIELD();
     rx.clear();
     sock_connected = at->modemConnect(host, port, mux, true);
+    // sock_connected = at->modemConnect(host, port, &mux, true);
+    // at->sockets[mux] = this;
+    // TODO:  When is the socket attached?
     return sock_connected;
   }
 };
@@ -578,6 +587,7 @@ public:
 
   bool gprsDisconnect() {
     // Shut the TCP/IP connection
+    // CIPSHUT will close *all* open connections
     sendAT(GF("+CIPSHUT"));
     if (waitResponse(60000L) != 1)
       return false;
@@ -791,6 +801,7 @@ public:
   /*
    * Battery functions
    */
+
   // Use: float vBatt = modem.getBattVoltage() / 1000.0;
   uint16_t getBattVoltage() {
     sendAT(GF("+CBC"));
@@ -853,6 +864,7 @@ protected:
       return 0;
     }
     streamSkipUntil(','); // Skip mux
+    maintain();  // look for a very quick response from the remote
     return stream.readStringUntil('\n').toInt();
   }
 
@@ -868,12 +880,19 @@ protected:
       return 0;
     }
 #endif
-    streamSkipUntil(','); // Skip mode 2/3
+    streamSkipUntil(','); // Skip Rx mode 2/normal or 3/HEX
     streamSkipUntil(','); // Skip mux
-    size_t len = stream.readStringUntil(',').toInt();
-    sockets[mux]->sock_available = stream.readStringUntil('\n').toInt();
+    size_t len_requested = stream.readStringUntil(',').toInt();
+    //  ^^ Requested number of data bytes (1-1460 bytes)to be read
+    size_t len_confirmed = stream.readStringUntil('\n').toInt();
+    if (len_confirmed > len_requested) {
+      DBG(len_requested - len_confirmed, "fewer bytes confirmed than requested!");
+    }
+    sockets[mux]->sock_available = len_confirmed;
+    // ^^ Confirmed number of data bytes to be read, which may be less than requested.
+    // 0 indicates that no data can be read.
 
-    for (size_t i=0; i<len; i++) {
+    for (size_t i=0; i<len_confirmed; i++) {
 #ifdef TINY_GSM_USE_HEX
       while (stream.available() < 2) { TINY_GSM_YIELD(); }
       char buf[4] = { 0, };
@@ -887,7 +906,9 @@ protected:
       sockets[mux]->rx.put(c);
     }
     waitResponse();
-    return len;
+    DBG("### READ:", len_confirmed, "from", mux);
+    maintain();  // Listen for a close or other URC
+    return len_confirmed;
   }
 
   size_t modemGetAvailable(uint8_t mux) {
@@ -902,6 +923,7 @@ protected:
     if (!result) {
       sockets[mux]->sock_connected = modemGetConnected(mux);
     }
+    maintain();  // Listen for a close or other URC
     return result;
   }
 
@@ -909,6 +931,7 @@ protected:
     sendAT(GF("+CIPSTATUS="), mux);
     int res = waitResponse(GF(",\"CONNECTED\""), GF(",\"CLOSED\""), GF(",\"CLOSING\""), GF(",\"INITIAL\""));
     waitResponse();
+    maintain();  // Listen for a close or other URC
     return 1 == res;
   }
 
@@ -969,9 +992,19 @@ public:
               sockets[mux]->got_data = true;
             }
             data = "";
+            DBG("### Got Data:", mux);
           } else {
             data += mode;
           }
+        } else if (data.endsWith(GF(GSM_NL "+RECEIVE:"))) {
+          int mux = stream.readStringUntil(',').toInt();
+          int len = stream.readStringUntil('\n').toInt();
+          if (mux >= 0 && mux < TINY_GSM_MUX_COUNT && sockets[mux]) {
+            sockets[mux]->got_data = true;
+            sockets[mux]->sock_available = len;
+          }
+          data = "";
+          DBG("### Got Data:", len, "on", mux);
         } else if (data.endsWith(GF("CLOSED" GSM_NL))) {
           int nl = data.lastIndexOf(GSM_NL, data.length()-8);
           int coma = data.indexOf(',', nl+2);

src/TinyGsmClientUBLOX.h

@@ -61,6 +61,11 @@ public:
     prev_check = 0;
     sock_connected = false;
     got_data = false;
+
+    // at->sockets[mux] = this;
+    //  ^^ TODO: attach the socket here at init?  Or later at connect?
+    // Currently done inconsistently between modems
+
     return true;
   }
 
@@ -81,8 +86,11 @@ public:
     }
     TINY_GSM_YIELD();
     rx.clear();
+    // sock_connected = at->modemConnect(host, port, mux);
     sock_connected = at->modemConnect(host, port, &mux);
     at->sockets[mux] = this;
+    // ^^ TODO: attach the socet after attempting connection or above at init?
+    // Currently done inconsistently between modems
     at->maintain();
     return sock_connected;
   }
@@ -109,7 +117,7 @@ public:
     rx.clear();
     at->maintain();
     while (sock_available > 0) {
-      sock_available -= at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
+      at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
       rx.clear();
       at->maintain();
     }
@@ -168,10 +176,10 @@ public:
         got_data = true;
         prev_check = millis();
       }
-      at->maintain();
       // TODO: Read directly into user buffer?
+      at->maintain();
       if (sock_available > 0) {
-        sock_available -= at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
+        at->modemRead(TinyGsmMin((uint16_t)rx.free(), sock_available), mux);
       } else {
         break;
       }
@@ -205,13 +213,13 @@ public:
   String remoteIP() TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
 private:
-  TinyGsmUBLOX* at;
-  uint8_t       mux;
-  uint16_t      sock_available;
-  uint32_t      prev_check;
-  bool          sock_connected;
-  bool          got_data;
-  RxFifo        rx;
+  TinyGsmUBLOX*   at;
+  uint8_t         mux;
+  uint16_t        sock_available;
+  uint32_t        prev_check;
+  bool            sock_connected;
+  bool            got_data;
+  RxFifo          rx;
 };
 
 
@@ -229,8 +237,10 @@ public:
     stop();
     TINY_GSM_YIELD();
     rx.clear();
+    // sock_connected = at->modemConnect(host, port, mux, true);
     sock_connected = at->modemConnect(host, port, &mux, true);
     at->sockets[mux] = this;
+    // TODO:  When is the socket attached?
     at->maintain();
     return sock_connected;
   }
@@ -772,6 +782,7 @@ protected:
 
   bool modemDisconnect(uint8_t mux) {
     TINY_GSM_YIELD();
+    if (!modemGetConnected(mux)) return true;
     if (isCatM) {  //  These modems allow a faster "asynchronous" close
       sendAT(GF("+USOCL="), mux, GF(",1"));
       int rsp = waitResponse(120000L);
@@ -798,7 +809,7 @@ protected:
     streamSkipUntil(','); // Skip mux
     int sent = stream.readStringUntil('\n').toInt();
     waitResponse();
-    maintain();  // look for a very quick response
+    maintain();  // look for a very quick response from the remote
     return sent;
   }
 
@@ -809,6 +820,7 @@ protected:
     }
     streamSkipUntil(','); // Skip mux
     size_t len = stream.readStringUntil(',').toInt();
+    sockets[mux]->sock_available = len;
     streamSkipUntil('\"');
 
     for (size_t i=0; i<len; i++) {
@@ -818,6 +830,8 @@ protected:
     }
     streamSkipUntil('\"');
     waitResponse();
+    DBG("### READ:", len, "from", mux);
+    maintain();  // Listen for a close or other URC
     return len;
   }
 
@@ -830,11 +844,13 @@ protected:
     if (res == 1) {
       streamSkipUntil(','); // Skip mux
       result = stream.readStringUntil('\n').toInt();
+      DBG("### DATA AVAILABLE:", result, "on", mux);
       waitResponse();
     }
     if (!result && res != 2 && res != 3) {  // Don't check modemGetConnected after an error
       sockets[mux]->sock_connected = modemGetConnected(mux);
     }
+    maintain();  // Listen for a close or other URC
     return result;
   }
 
@@ -860,6 +876,7 @@ protected:
     // 9: the socket is in LAST_ACK status
     // 10: the socket is in TIME_WAIT status
     waitResponse();
+    maintain();  // Listen for a close or other URC
     return (result != 0);
   }
 
@@ -895,7 +912,7 @@ public:
       TINY_GSM_YIELD();
       while (stream.available() > 0) {
         int a = stream.read();
-        if (a < 0) continue;
+        if (a <= 0) continue; // Skip 0x00 bytes, just in case
         data += (char)a;
         if (r1 && data.endsWith(r1)) {
           index = 1;
@@ -914,19 +931,20 @@ public:
           goto finish;
         } else if (data.endsWith(GF(GSM_NL "+UUSORD:"))) {
           int mux = stream.readStringUntil(',').toInt();
-          streamSkipUntil('\n');
+          int len = stream.readStringUntil('\n').toInt();
           if (mux >= 0 && mux < TINY_GSM_MUX_COUNT && sockets[mux]) {
             sockets[mux]->got_data = true;
+            sockets[mux]->sock_available = len;
           }
           data = "";
-          DBG("### Got Data:", mux);
+          DBG("### Got Data:", len, "on", mux);
         } else if (data.endsWith(GF(GSM_NL "+UUSOCL:"))) {
           int mux = stream.readStringUntil('\n').toInt();
           if (mux >= 0 && mux < TINY_GSM_MUX_COUNT && sockets[mux]) {
             sockets[mux]->sock_connected = false;
           }
           data = "";
-          DBG("### Closed:", mux);
+          DBG("### Closed: ", mux);
         }
       }
     } while (millis() - startMillis < timeout);

src/TinyGsmClientXBee.h

@@ -213,10 +213,10 @@ public:
   String remoteIP() TINY_GSM_ATTR_NOT_IMPLEMENTED;
 
 private:
-  TinyGsmXBee*  at;
-  uint8_t       mux;
-  bool          sock_connected;
-  // RxFifo        rx;
+  TinyGsmXBee*    at;
+  uint8_t         mux;
+  bool            sock_connected;
+  // RxFifo          rx;
 };
 
 
@@ -992,8 +992,8 @@ finish:
     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);
+      // Default guard time is 1s, but the init fxn decreases it to 100 ms
+      delay(guardTime + 50);
       streamWrite(GF("+++"));  // enter command mode
       int res = waitResponse(guardTime*2);
       success = (1 == res);

src/TinyGsmCommon.h

@@ -10,7 +10,7 @@
 #define TinyGsmCommon_h
 
 // The current library version number
-#define TINYGSM_VERSION "0.6.1"
+#define TINYGSM_VERSION "0.6.2"
 
 #if defined(SPARK) || defined(PARTICLE)
   #include "Particle.h"