added optional disconnection of modem data session after each send

OpenTracker/gsm.ino

@@ -345,14 +345,33 @@ int gsm_get_modem_status() {
 }
 
 int gsm_disconnect() {
-  debug_print(F("gsm_disconnect() started"));
+    int ret = 0;
+    debug_print(F("gsm_disconnect() started"));
+  #if GSM_DISCONNECT_AFTER_SEND
+    //disconnect GSM
+    gsm_port.print("AT+QIDEACT\r");
+    gsm_wait_for_reply(0,0);
+
+    //check if result contains DEACT OK
+    char *tmp = strstr(modem_reply, "DEACT OK");
+
+    if(tmp!=NULL) {
+      debug_print(F("gsm_disconnect(): DEACT OK found"));
+      ret = 1;
+    } else {
+      debug_print(F("gsm_disconnect(): DEACT OK not found."));
+    }
+  #else
+    //close connection, if previous attempts left it open
+    gsm_port.print("AT+QICLOSE\r");
+    gsm_wait_for_reply(0,0);
+
+    //ignore errors (will be taken care during connect)
+    ret = 1;
+  #endif
 
-  //close connection, if previous attempts left it open
-  gsm_port.print("AT+QICLOSE\r");
-  gsm_wait_for_reply(0,0);
-
   debug_print(F("gsm_disconnect() completed"));
-  return 1;
+  return ret;
 }
 
 int gsm_set_apn()  {

OpenTracker/tracker.h.example

@@ -21,6 +21,7 @@
 
 #define GSM_MODEM_COMMAND_TIMEOUT 10
 #define GSM_SEND_FAILURES_REBOOT 30         // 0=disabled, increase to set the number of GSM failures that will trigger a reboot of the opentracker device
+#define GSM_DISCONNECT_AFTER_SEND 0         // 0=keep modem data session active, only close TCP connection (default), 1=close data session after each send
 
 #define ENGINE_RUNNING_LOG_FAST_AS_POSSIBLE 0 // 1=when the engine is running send interval is ignored