fix(modem): Fixed incorrect dial command format

ATD command is used to switch generic device to the data mode
by dialing GPRS_SRC. The generic version of the command was incorrect
`ATD*99##` (containing extra trailing # char, which is accepted by most
devices). Command has been fixed, but the extra #'s been kept for devices
that we cannot test (to be fixed in IDFGH-9470).

Closes #433

Author: david-cermak

components/esp_modem/include/cxx_include/esp_modem_command_library.hpp

@@ -54,7 +54,7 @@ command_result power_down_sim76xx(CommandableIf *t);
 command_result power_down_sim70xx(CommandableIf *t);
 command_result set_network_bands_sim76xx(CommandableIf *t, const std::string &mode, const int *bands, int size);
 command_result power_down_sim8xx(CommandableIf *t);
-command_result set_data_mode_sim8xx(CommandableIf *t);
+command_result set_data_mode_alt(CommandableIf *t);
 command_result set_pdp_context(CommandableIf *t, PdpContext &pdp, uint32_t timeout_ms);
 
 /**

components/esp_modem/include/cxx_include/esp_modem_dce_module.hpp

@@ -144,6 +144,8 @@ class SIM7070: public GenericModule {
     using GenericModule::GenericModule;
 public:
     command_result power_down() override;
+    command_result set_data_mode() override;
+
 };
 
 /**
@@ -162,7 +164,6 @@ class SIM800: public GenericModule {
     using GenericModule::GenericModule;
 public:
     command_result power_down() override;
-    command_result set_data_mode() override;
 };
 
 /**

components/esp_modem/src/esp_modem_command_library.cpp

@@ -277,13 +277,13 @@ command_result set_pdp_context(CommandableIf *t, PdpContext &pdp)
 command_result set_data_mode(CommandableIf *t)
 {
     ESP_LOGV(TAG, "%s", __func__ );
-    return generic_command(t, "ATD*99##\r", "CONNECT", "ERROR", 5000);
+    return generic_command(t, "ATD*99#\r", "CONNECT", "ERROR", 5000);
 }
 
-command_result set_data_mode_sim8xx(CommandableIf *t)
+command_result set_data_mode_alt(CommandableIf *t)
 {
     ESP_LOGV(TAG, "%s", __func__ );
-    return generic_command(t, "ATD*99#\r", "CONNECT", "ERROR", 5000);
+    return generic_command(t, "ATD*99##\r", "CONNECT", "ERROR", 5000);
 }
 
 command_result resume_data_mode(CommandableIf *t)

components/esp_modem/src/esp_modem_modules.cpp

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2021-2023 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2021-2024 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -67,6 +67,11 @@ command_result SIM7070::power_down()
     return dce_commands::power_down_sim70xx(dte.get());
 }
 
+command_result SIM7070::set_data_mode()
+{
+    return dce_commands::set_data_mode_alt(dte.get());
+}
+
 command_result SIM7000::power_down()
 {
     return dce_commands::power_down_sim70xx(dte.get());
@@ -77,11 +82,6 @@ command_result SIM800::power_down()
     return dce_commands::power_down_sim8xx(dte.get());
 }
 
-command_result SIM800::set_data_mode()
-{
-    return dce_commands::set_data_mode_sim8xx(dte.get());
-}
-
 command_result BG96::set_pdp_context(esp_modem::PdpContext &pdp)
 {
     return dce_commands::set_pdp_context(dte.get(), pdp, 300);

components/esp_modem/test/host_test/main/LoopbackTerm.cpp

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2022-2023 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2022-2024 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Unlicense OR CC0-1.0
  */
@@ -36,7 +36,7 @@ int LoopbackTerm::write(uint8_t *data, size_t len)
         } else if (command == "ATO\r") {
             response = "ERROR\r\n";
         } else if (command.find("ATD") != std::string::npos) {
-            response = "CONNECT\r\n";
+            response = "CONNECT\n";
         } else if (command.find("AT+CSQ\r") != std::string::npos) {
             response = "+CSQ: 123,456\n\r\nOK\r\n";
         } else if (command.find("AT+CGMM\r") != std::string::npos) {
@@ -74,6 +74,9 @@ int LoopbackTerm::write(uint8_t *data, size_t len)
     }
     if (len > 2 && data[0] == 0xf9) { // Simple CMUX responder
         // turn the request into a reply -> implements CMUX loopback
+        // Note: This simple CMUX responder only updates CMUX headers and replaces payload.
+        // It means that all responses (that we test) must be shorter or equal to the requests
+        // For example ATD (dial command): sizeof("ATD*99#") >= sizeof("CONNECT");
         if (data[2] == 0x3f || data[2] == 0x53) {  // SABM command
             data[2] = 0x73;
         } else if (data[2] == 0xef) { // Generic request