UBLOX cellular context activation updated for C030_R412M and updated AUTH configuration

features/cellular/framework/API/CellularContext.h

@@ -54,7 +54,8 @@ public:
     enum AuthenticationType {
         NOAUTH = 0,
         PAP,
-        CHAP
+        CHAP,
+        AUTOMATIC
     };
 
     /*  whether the additional exception reports are allowed to be sent when the maximum uplink rate is reached */

features/cellular/framework/targets/UBLOX/AT/UBLOX_AT.cpp

@@ -16,8 +16,6 @@
  */
 
 #include "UBLOX_AT.h"
-#include "UBLOX_AT_CellularNetwork.h"
-#include "UBLOX_AT_CellularContext.h"
 
 using namespace mbed;
 using namespace events;
@@ -72,7 +70,8 @@ AT_CellularNetwork *UBLOX_AT::open_network_impl(ATHandler &at)
 
 AT_CellularContext *UBLOX_AT::create_context_impl(ATHandler &at, const char *apn, bool cp_req, bool nonip_req)
 {
-    return new UBLOX_AT_CellularContext(at, this, apn, cp_req, nonip_req);
+    ubx_context = new UBLOX_AT_CellularContext(at, this, apn, cp_req, nonip_req);
+    return  ubx_context;
 }
 
 #if MBED_CONF_UBLOX_AT_PROVIDE_DEFAULT
@@ -89,3 +88,127 @@ CellularDevice *CellularDevice::get_default_instance()
 }
 #endif
 
+nsapi_error_t UBLOX_AT::init()
+{
+    _at->lock();
+    _at->flush();
+    _at->cmd_start("AT");
+    _at->cmd_stop_read_resp();
+
+#ifdef TARGET_UBLOX_C027
+    _at->cmd_start("AT+CFUN=0");
+    _at->cmd_stop_read_resp();
+    if (_at->get_last_error() == NSAPI_ERROR_OK) {
+        _at->cmd_start("ATE0"); // echo off
+        _at->cmd_stop_read_resp();
+        _at->cmd_start("AT+CMEE=1"); // verbose responses
+        _at->cmd_stop_read_resp();
+        config_authentication_parameters();
+        _at->cmd_start("AT+CFUN=1"); // set full functionality
+        _at->cmd_stop_read_resp();
+    }
+#else
+    _at->cmd_start("AT+CFUN=4");
+    _at->cmd_stop_read_resp();
+    if (_at->get_last_error() == NSAPI_ERROR_OK) {
+        _at->cmd_start("ATE0"); // echo off
+        _at->cmd_stop_read_resp();
+        _at->cmd_start("AT+CMEE=1"); // verbose responses
+        _at->cmd_stop_read_resp();
+        config_authentication_parameters();
+        _at->cmd_start("AT+CFUN=1"); // set full functionality
+        _at->cmd_stop_read_resp();
+    }
+#endif
+
+    return _at->unlock_return_error();
+}
+
+nsapi_error_t UBLOX_AT::config_authentication_parameters()
+{
+    char *config = NULL;
+    nsapi_error_t err;
+    char imsi[MAX_IMSI_LENGTH + 1];
+
+    if (apn == NULL) {
+        err = get_imsi(imsi);
+        if (err == NSAPI_ERROR_OK) {
+            config = (char *)apnconfig(imsi);
+        }
+    }
+
+    ubx_context->get_next_credentials(&config);
+    apn = ubx_context->get_apn();
+    pwd = ubx_context->get_pwd();
+    uname = ubx_context->get_uname();
+    auth = ubx_context->get_auth();
+
+    auth = (*uname && *pwd) ? auth : CellularContext::NOAUTH;
+    err = set_authentication_parameters(apn, uname, pwd, auth);
+
+    return err;
+}
+
+nsapi_error_t UBLOX_AT::set_authentication_parameters(const char *apn,
+                                                      const char *username,
+                                                      const char *password,
+                                                      CellularContext::AuthenticationType auth)
+{
+    int modem_security = ubx_context->nsapi_security_to_modem_security(auth);
+
+    _at->cmd_start("AT+CGDCONT=1,\"IP\",");
+    _at->write_string(apn);
+    _at->cmd_stop();
+    _at->resp_start();
+    _at->resp_stop();
+
+    if (_at->get_last_error() == NSAPI_ERROR_OK) {
+#ifdef TARGET_UBLOX_C030_R41XM
+        if (modem_security == CellularContext::CHAP) {
+            _at->cmd_start("AT+UAUTHREQ=1,");
+            _at->write_int(modem_security);
+            _at->write_string(password);
+            _at->write_string(username);
+            _at->cmd_stop();
+            _at->resp_start();
+            _at->resp_stop();
+        } else if (modem_security == CellularContext::NOAUTH) {
+            _at->cmd_start("AT+UAUTHREQ=1,");
+            _at->write_int(modem_security);
+            _at->cmd_stop();
+            _at->resp_start();
+            _at->resp_stop();
+        } else {
+            _at->cmd_start("AT+UAUTHREQ=1,");
+            _at->write_int(modem_security);
+            _at->write_string(username);
+            _at->write_string(password);
+            _at->cmd_stop();
+            _at->resp_start();
+            _at->resp_stop();
+        }
+#else
+        _at->cmd_start("AT+UAUTHREQ=1,");
+        _at->write_int(modem_security);
+        _at->write_string(username);
+        _at->write_string(password);
+        _at->cmd_stop();
+        _at->resp_start();
+        _at->resp_stop();
+#endif
+    }
+
+    return _at->get_last_error();
+}
+
+nsapi_error_t UBLOX_AT::get_imsi(char *imsi)
+{
+    _at->lock();
+    _at->cmd_start("AT+CIMI");
+    _at->cmd_stop();
+    _at->resp_start();
+    _at->read_string(imsi, MAX_IMSI_LENGTH + 1);
+    _at->resp_stop();
+
+    return _at->unlock_return_error();
+}

features/cellular/framework/targets/UBLOX/AT/UBLOX_AT.h

@@ -27,7 +27,11 @@
 #endif
 #endif /* TARGET_FF_ARDUINO */
 
+#include "APN_db.h"
 #include "AT_CellularDevice.h"
+#include "AT_CellularContext.h"
+#include "UBLOX_AT_CellularNetwork.h"
+#include "UBLOX_AT_CellularContext.h"
 
 namespace mbed {
 
@@ -40,6 +44,32 @@ protected: // AT_CellularDevice
     virtual AT_CellularContext *create_context_impl(ATHandler &at, const char *apn, bool cp_req = false, bool nonip_req = false);
 public: // NetworkInterface
     void handle_urc(FileHandle *fh);
+
+    virtual nsapi_error_t init();
+
+private:
+
+    UBLOX_AT_CellularContext *ubx_context;
+
+    /** Length of IMSI buffer.
+     */
+    static const int MAX_IMSI_LENGTH = 15;
+
+    const char *apn;
+    const char *uname;
+    const char *pwd;
+
+    /** The type of authentication to use.
+     */
+    CellularContext::AuthenticationType auth;
+
+    nsapi_error_t config_authentication_parameters();
+
+    nsapi_error_t set_authentication_parameters(const char *apn, const char *username, const char *password, CellularContext::AuthenticationType auth);
+
+    /** Read IMSI of modem.
+     */
+    nsapi_error_t get_imsi(char *imsi);
 };
 
 } // namespace mbed

features/cellular/framework/targets/UBLOX/AT/UBLOX_AT_CellularContext.cpp

@@ -25,7 +25,7 @@ UBLOX_AT_CellularContext::UBLOX_AT_CellularContext(ATHandler &at, CellularDevice
     AT_CellularContext(at, device, apn, cp_req, nonip_req)
 {
     // The authentication to use
-    _auth = NSAPI_SECURITY_UNKNOWN;
+    _auth = NOAUTH;
 }
 
 UBLOX_AT_CellularContext::~UBLOX_AT_CellularContext()
@@ -49,12 +49,42 @@ void UBLOX_AT_CellularContext::do_connect()
 {
     _at.lock();
     _cb_data.error = NSAPI_ERROR_NO_CONNECTION;
+    CellularNetwork::RadioAccessTechnology rat = read_radio_technology();
 
     // Attempt to establish a connection
-#ifdef TARGET_UBLOX_C030_R41XM
+#ifndef TARGET_UBLOX_C030_R41XM
+    _cb_data.error = define_context();
+#elif TARGET_UBLOX_C030_R410M
+    _is_context_active = true;
+    _is_context_activated = true;
     _cb_data.error = NSAPI_ERROR_OK;
-#else
+#elif TARGET_UBLOX_C030_R412M
-    _cb_data.error = open_data_channel();
+    if (rat == CellularNetwork::RadioAccessTechnology::RAT_EGPRS) {
+        if (!_is_context_active) {
+            _at.set_at_timeout(150 * 1000);
+            _at.cmd_start("AT+CGACT=1,1");
+            _at.cmd_stop();
+            _at.resp_start();
+            _at.resp_stop();
+
+            _at.cmd_start("AT+CGACT?");
+            _at.cmd_stop();
+            _at.resp_start("+CGACT:");
+            _at.skip_param(1);
+            _is_context_activated = _at.read_int();
+            _at.resp_stop();
+            _at.restore_at_timeout();
+            if (_is_context_activated == true) {
+                _cid = 1;
+                _is_context_active = true;
+                _cb_data.error = NSAPI_ERROR_OK;
+            }
+        }
+    } else if (rat == CellularNetwork::RadioAccessTechnology::RAT_CATM1 || rat == CellularNetwork::RadioAccessTechnology::RAT_NB1) {
+        _is_context_active = true;
+        _is_context_activated = true;
+        _cb_data.error = NSAPI_ERROR_OK;
+    }
 #endif
     if (_cb_data.error != NSAPI_ERROR_OK) {
         // If new PSD context was created and failed to activate, delete it
@@ -72,7 +102,8 @@ void UBLOX_AT_CellularContext::do_connect()
     }
 }
 
-nsapi_error_t UBLOX_AT_CellularContext::open_data_channel()
+#ifndef TARGET_UBLOX_C030_R41XM
+nsapi_error_t UBLOX_AT_CellularContext::define_context()
 {
     bool success = false;
     int active = 0;
@@ -106,11 +137,11 @@ nsapi_error_t UBLOX_AT_CellularContext::open_data_channel()
         do {
             get_next_credentials(&config);
             if (_uname && _pwd) {
-                _auth = (*_uname && *_pwd) ? _auth : NSAPI_SECURITY_NONE;
+                _auth = (*_uname && *_pwd) ? _authentication_type : NOAUTH;
             } else {
-                _auth = NSAPI_SECURITY_NONE;
+                _auth = NOAUTH;
             }
-            success = activate_profile(_apn, _uname, _pwd);
+            success = activate_profile(_apn, _uname, _pwd, _auth);
         } while (!success && config && *config);
     } else {
         // If the profile is already active, we're good
@@ -124,7 +155,8 @@ nsapi_error_t UBLOX_AT_CellularContext::open_data_channel()
 
 bool UBLOX_AT_CellularContext::activate_profile(const char *apn,
                                                 const char *username,
-                                                const char *password)
+                                                const char *password,
+                                                AuthenticationType auth)
 {
     bool activated = false;
     bool success = false;
@@ -175,75 +207,73 @@ bool UBLOX_AT_CellularContext::activate_profile(const char *apn,
         _at.resp_start();
         _at.resp_stop();
 
-        // Set up the authentication protocol
+        _at.cmd_start("AT+UPSD=" PROFILE ",6,");
-        // 0 = none
+        _at.write_int(nsapi_security_to_modem_security(auth));
-        // 1 = PAP (Password Authentication Protocol)
+        _at.cmd_stop();
-        // 2 = CHAP (Challenge Handshake Authentication Protocol)
+        _at.resp_start();
-        for (int protocol = nsapi_security_to_modem_security(NSAPI_SECURITY_NONE);
+        _at.resp_stop();
-                success && (protocol <= nsapi_security_to_modem_security(NSAPI_SECURITY_CHAP)); protocol++) {
-            if ((_auth == NSAPI_SECURITY_UNKNOWN) || (nsapi_security_to_modem_security(_auth) == protocol)) {
-                _at.cmd_start("AT+UPSD=" PROFILE ",6,");
-                _at.write_int(protocol);
-                _at.cmd_stop();
-                _at.resp_start();
-                _at.resp_stop();
 
-                if (_at.get_last_error() == NSAPI_ERROR_OK) {
+        if (_at.get_last_error() == NSAPI_ERROR_OK) {
-                    // Activate, wait upto 30 seconds for the connection to be made
+            // Activate, wait upto 30 seconds for the connection to be made
-                    _at.set_at_timeout(30000);
+            _at.set_at_timeout(30000);
-                    _at.cmd_start("AT+UPSDA=" PROFILE ",3");
+            _at.cmd_start("AT+UPSDA=" PROFILE ",3");
+            _at.cmd_stop();
+            _at.resp_start();
+            _at.resp_stop();
+            _at.restore_at_timeout();
+
+            if (_at.get_last_error() == NSAPI_ERROR_OK) {
+                Timer t1;
+                t1.start();
+                while (!(t1.read() >= 180)) {
+                    _at.cmd_start("AT+UPSND=" PROFILE ",8");
                     _at.cmd_stop();
-                    _at.resp_start();
+                    _at.resp_start("+UPSND:");
+                    _at.skip_param(2);
+                    _at.read_int() ? activated = true : activated = false;
                     _at.resp_stop();
-                    _at.restore_at_timeout();
 
-                    if (_at.get_last_error() == NSAPI_ERROR_OK) {
+                    if (activated) {  //If context is activated, exit while loop and return status
-                        Timer t1;
+                        break;
-                        t1.start();
-                        while (!(t1.read() >= 180)) {
-                            _at.cmd_start("AT+UPSND=" PROFILE ",8");
-                            _at.cmd_stop();
-                            _at.resp_start("+UPSND:");
-                            _at.skip_param(2);
-                            _at.read_int() ? activated = true : activated = false;
-                            _at.resp_stop();
-
-                            if (activated) {  //If context is activated, exit while loop and return status
-                                break;
-                            }
-                            rtos::ThisThread::sleep_for(5000); //Wait for 5 seconds and then try again
-                        }
-                        t1.stop();
                     }
+                    wait_ms(5000);    //Wait for 5 seconds and then try again
                 }
+                t1.stop();
             }
         }
     }
 
     return activated;
 }
+#endif
 
 // Convert nsapi_security_t to the modem security numbers
-int UBLOX_AT_CellularContext::nsapi_security_to_modem_security(nsapi_security_t nsapi_security)
+int UBLOX_AT_CellularContext::nsapi_security_to_modem_security(AuthenticationType nsapi_security)
 {
     int modem_security = 3;
 
     switch (nsapi_security) {
-        case NSAPI_SECURITY_NONE:
+        case NOAUTH:
             modem_security = 0;
             break;
-        case NSAPI_SECURITY_PAP:
+        case PAP:
             modem_security = 1;
             break;
-        case NSAPI_SECURITY_CHAP:
+        case CHAP:
             modem_security = 2;
             break;
-        case NSAPI_SECURITY_UNKNOWN:
+#ifndef TARGET_UBLOX_C030_R41XM
+        case AUTOMATIC:
             modem_security = 3;
             break;
         default:
             modem_security = 3;
             break;
+#else
+        default:
+            modem_security = 0;
+            break;
+#endif
     }
 
     return modem_security;
@@ -274,10 +304,7 @@ nsapi_error_t UBLOX_AT_CellularContext::get_imsi(char *imsi)
     _at.cmd_start("AT+CIMI");
     _at.cmd_stop();
     _at.resp_start();
-    int len = _at.read_string(imsi, MAX_IMSI_LENGTH);
+    _at.read_string(imsi, MAX_IMSI_LENGTH + 1);
-    if (len > 0) {
-        imsi[len] = '\0';
-    }
     _at.resp_stop();
 
     return _at.unlock_return_error();
@@ -298,4 +325,62 @@ const char *UBLOX_AT_CellularContext::get_gateway()
     return get_ip_address();
 }
 
+const char *UBLOX_AT_CellularContext::get_apn()
+{
+    return _apn;
+}
+
+const char *UBLOX_AT_CellularContext::get_uname()
+{
+    return _uname;
+}
+
+const char *UBLOX_AT_CellularContext::get_pwd()
+{
+    return _pwd;
+}
+
+CellularContext::AuthenticationType UBLOX_AT_CellularContext::get_auth()
+{
+    return _authentication_type;
+}
+
+CellularNetwork::RadioAccessTechnology UBLOX_AT_CellularContext::read_radio_technology()
+{
+    int act;
+    CellularNetwork::RadioAccessTechnology rat;
+
+    _at.cmd_start("AT+URAT?");
+    _at.cmd_stop();
+    _at.resp_start("+URAT:");
+    act = _at.read_int();
+    _at.resp_stop();
+
+    switch (act) {
+        case 0:
+            rat = CellularNetwork::RadioAccessTechnology::RAT_GSM;
+            break;
+        case 1:
+            rat = CellularNetwork::RadioAccessTechnology::RAT_GSM;
+            break;
+        case 2:
+            rat = CellularNetwork::RadioAccessTechnology::RAT_UTRAN;
+            break;
+        case 7:
+            rat = CellularNetwork::RadioAccessTechnology::RAT_CATM1;
+            break;
+        case 8:
+            rat = CellularNetwork::RadioAccessTechnology::RAT_NB1;
+            break;
+        case 9:
+            rat = CellularNetwork::RadioAccessTechnology::RAT_EGPRS;
+            break;
+        default:
+            rat = CellularNetwork::RadioAccessTechnology::RAT_UNKNOWN;
+            break;
+    }
+
+    return rat;
+}
+
 } /* namespace mbed */

features/cellular/framework/targets/UBLOX/AT/UBLOX_AT_CellularContext.h

@@ -18,6 +18,7 @@
 #define UBLOX_AT_CELLULARCONTEXT_H_
 
 #include "AT_CellularContext.h"
+#include "UBLOX_AT_CellularNetwork.h"
 
 namespace mbed {
 
@@ -29,9 +30,35 @@ public:
     virtual void do_connect();
     virtual const char *get_gateway();
 
+    const char *get_apn(void);
+    const char *get_uname(void);
+    const char *get_pwd(void);
+    CellularContext::AuthenticationType get_auth(void);
+
+    /** Convert nsapi_security_t to the modem security numbers.
+     *
+     * @param nsapi_security      Security protocol.
+     * @return                    Modem security numbers.
+     */
+    int nsapi_security_to_modem_security(AuthenticationType nsapi_security);
+
+    /** Get the next set of credentials from the database.
+     */
+    void get_next_credentials(char **config);
+
+    CellularNetwork::RadioAccessTechnology read_radio_technology(void);
+
 protected:
     virtual NetworkStack *get_stack();
 
+    /** Connect the on board IP stack of the modem.
+     *
+     * @return      True if successful, otherwise false.
+     */
+#ifndef TARGET_UBLOX_C030_R41XM
+    nsapi_error_t define_context();
+#endif
+
 private:
 
     /** Length of IMSI buffer.
@@ -40,13 +67,7 @@ private:
 
     /** The type of authentication to use.
      */
-    nsapi_security_t _auth;
+    AuthenticationType _auth;
-
-    /** Connect the on board IP stack of the modem.
-     *
-     * @return      True if successful, otherwise false.
-     */
-    nsapi_error_t open_data_channel();
 
     /** Activate one of the on-board modem's connection profiles.
      *
@@ -54,18 +75,13 @@ private:
      * @param username The user name to use.
      * @param password The password to use.
      * @param auth     The authentication method to use
-     *                 (NSAPI_SECURITY_NONE, NSAPI_SECURITY_PAP,
+     *                 (NOAUTH, PAP,
-     *                 NSAPI_SECURITY_CHAP or NSAPI_SECURITY_UNKNOWN).
+     *                 CHAP or AUTOMATIC).
      * @return         True if successful, otherwise false.
      */
-    bool activate_profile(const char *apn, const char *username, const char *password);
+#ifndef TARGET_UBLOX_C030_R41XM
-
+    bool activate_profile(const char *apn, const char *username, const char *password, AuthenticationType auth);
-    /** Convert nsapi_security_t to the modem security numbers.
+#endif
-     *
-     * @param nsapi_security      Security protocol.
-     * @return                    Modem security numbers.
-     */
-    int nsapi_security_to_modem_security(nsapi_security_t nsapi_security);
 
     /** Disconnect the on board IP stack of the modem.
      *
@@ -76,10 +92,6 @@ private:
     /** Read IMSI of modem.
      */
     nsapi_error_t get_imsi(char *imsi);
-
-    /** Get the next set of credentials from the database.
-     */
-    void get_next_credentials(char **config);
 };
 
 } /* namespace mbed */

features/cellular/framework/targets/UBLOX/AT/UBLOX_AT_CellularNetwork.cpp

@@ -34,35 +34,74 @@ UBLOX_AT_CellularNetwork::~UBLOX_AT_CellularNetwork()
 nsapi_error_t UBLOX_AT_CellularNetwork::set_access_technology_impl(RadioAccessTechnology opRat)
 {
     nsapi_error_t ret = NSAPI_ERROR_OK;
+    CellularNetwork::AttachStatus status;
 
+    get_attach(status);
+    if (status == Attached) {
+        tr_debug("RAT should only be set in detached state");
+        return NSAPI_ERROR_UNSUPPORTED;
+    }
+
+    _at.lock();
     switch (opRat) {
-#if defined(TARGET_UBLOX_C030_U201) || defined(TARGET_UBLOX_C027)
-        case RAT_GSM:
-        case RAT_GSM_COMPACT:
-            break;
         case RAT_EGPRS:
+#if defined (TARGET_UBLOX_C030_R412M)
+            _at.cmd_start("AT+URAT=9,8");
+            _at.cmd_stop_read_resp();
+            break;
+#endif
+#if defined(TARGET_UBLOX_C030_U201)
+        case RAT_GSM:
+            _at.cmd_start("AT+URAT=0,0");
+            _at.cmd_stop_read_resp();
             break;
-#elif defined(TARGET_UBLOX_C030_U201)
         case RAT_UTRAN:
-            break;
         case RAT_HSDPA:
-            break;
         case RAT_HSUPA:
-            break;
         case RAT_HSDPA_HSUPA:
+            _at.cmd_start("AT+URAT=2,2");
+            _at.cmd_stop_read_resp();
             break;
 #elif defined(TARGET_UBLOX_C030_R41XM)
         case RAT_CATM1:
+            _at.cmd_start("AT+URAT=7,8");
+            _at.cmd_stop_read_resp();
             break;
-#elif defined(TARGET_UBLOX_C030_R41XM) || defined(TARGET_UBLOX_C030_N211)
         case RAT_NB1:
+            _at.cmd_start("AT+URAT=8,7");
+            _at.cmd_stop_read_resp();
             break;
 #endif
-        default: {
+        default:
             _op_act = RAT_UNKNOWN;
             ret = NSAPI_ERROR_UNSUPPORTED;
-        }
+            break;
     }
+    _at.unlock();
+    ubx_reboot();
 
     return (ret);
 }
+
+nsapi_error_t UBLOX_AT_CellularNetwork::ubx_reboot()
+{
+    _at.lock();
+    _at.cmd_start("AT+CFUN=15");
+    _at.cmd_stop_read_resp();
+
+    Timer t1;
+    t1.start();
+    while (!(t1.read() >= 30)) {
+        _at.cmd_start("ATE0"); // echo off
+        _at.cmd_stop_read_resp();
+        if (_at.get_last_error() == NSAPI_ERROR_OK) {
+            break;
+        } else {
+            _at.clear_error();
+            wait_ms(1000);
+        }
+    }
+    t1.stop();
+    _at.unlock();
+    return _at.get_last_error();
+}

features/cellular/framework/targets/UBLOX/AT/UBLOX_AT_CellularNetwork.h

@@ -18,7 +18,11 @@
 #ifndef UBLOX_AT_CELLULAR_NETWORK_H_
 #define UBLOX_AT_CELLULAR_NETWORK_H_
 
+#include "CellularLog.h"
+#include "drivers/Timer.h"
+#include "mbed_wait_api.h"
 #include "AT_CellularNetwork.h"
+#include "AT_CellularContext.h"
 
 namespace mbed {
 
@@ -27,6 +31,8 @@ public:
     UBLOX_AT_CellularNetwork(ATHandler &atHandler);
     virtual ~UBLOX_AT_CellularNetwork();
 
+    nsapi_error_t ubx_reboot();
+
 protected:
     virtual nsapi_error_t set_access_technology_impl(RadioAccessTechnology opRat);
 };

features/cellular/framework/targets/UBLOX/N2XX/UBLOX_N2XX.cpp

@@ -68,7 +68,7 @@ nsapi_error_t UBLOX_N2XX::init()
 {
     _at->lock();
     _at->flush();
-    _at->cmd_start("AT"); // echo off
+    _at->cmd_start("AT");
     _at->cmd_stop_read_resp();
 
     _at->cmd_start("AT+CMEE=1"); // verbose responses