diff --git a/examples/api_test/api_test.ino b/examples/api_test/api_test.ino
index 0546edc9..736a52da 100644
--- a/examples/api_test/api_test.ino
+++ b/examples/api_test/api_test.ino
@@ -1,20 +1,20 @@
 #include "KiteLib.h"
 
 ESP8266 wifi = Kite.ModuleA;
-//SX1278 lora = Kite.ModuleB;
+SX1278 lora = Kite.ModuleB;
 //HC05 bluetooth = Kite.ModuleB;
 
-//Packet pack("01:23:45:67:89:AB:CD:EF", "Hello World! (by LoRa)");
+Packet pack("01:23:45:67:89:AB:CD:EF", "Hello World! (by LoRa)");
 
 void setup() {
   Serial.begin(9600);
 
   Serial.print("[ESP8266] Connecting ... ");
-  uint8_t state = wifi.begin(9600);
+  byte state = wifi.begin(9600);
   if(state == ERR_NONE) {
     Serial.println("success!");
   } else {
-    Serial.print("failed, code ");
+    Serial.print("failed, code 0x");
     Serial.println(state, HEX);
   }
 
@@ -23,29 +23,43 @@ void setup() {
   if(state == ERR_NONE) {
     Serial.println("success!");
   } else {
-    Serial.print("failed, code ");
+    Serial.print("failed, code 0x");
     Serial.println(state, HEX);
   }
 
   Serial.print("[ESP8266] Sending GET request ... ");
   String response;
-  uint16_t http_code = wifi.HttpGet("http://www.httpbin.org/ip", response);
+  int http_code = wifi.HttpGet("http://www.httpbin.org/ip", response);
   if(http_code == 200) {
     Serial.println("success!");
     Serial.println("[ESP8266] Response:\n");
     Serial.println(response);
   } else {
-    Serial.print("failed, code ");
+    Serial.print("failed, code 0x");
     Serial.println(http_code, HEX);
   }
 
-  //lora.begin();
+  Serial.print("[SX1278] Initializing ... ");
+  state = lora.begin();
+  if(state == ERR_NONE) {
+    Serial.println("success!");
+  } else {
+    Serial.print("failed, code 0x");
+    Serial.println(state, HEX);
+  }
 
   //bluetooth.begin(9600);
 }
 
 void loop() {
-  //lora.transmit(pack);
+  Serial.print("[SX1278] Transmitting packet ... ");
+  byte state = lora.transmit(pack);
+  if(state == ERR_NONE) {
+    Serial.println("success!");
+  } else {
+    Serial.print("failed, code 0x");
+    Serial.println(state, HEX);
+  }
 
   //bluetooth.println("Hello World! (by Blueooth)");
   
diff --git a/src/ESP8266.cpp b/src/ESP8266.cpp
index f74194e2..d51abdec 100644
--- a/src/ESP8266.cpp
+++ b/src/ESP8266.cpp
@@ -11,7 +11,7 @@ uint8_t ESP8266::begin(long speed) {
   _mod->init(USE_UART, INT_NONE);
   _mod->ATemptyBuffer();
   if(!_mod->ATsendCommand("AT")) {
-    return(ERR_UNKNOWN);
+    return(ERR_AT_FAILED);
   }
   return(ERR_NONE);
 }
@@ -19,7 +19,7 @@ uint8_t ESP8266::begin(long speed) {
 uint8_t ESP8266::reset() {
   // send the reset command
   if(!_mod->ATsendCommand("AT+RST")) {
-    return(ERR_UNKNOWN);
+    return(ERR_AT_FAILED);
   }
   
   // wait for the module to start
@@ -35,13 +35,13 @@ uint8_t ESP8266::reset() {
     }
   }
   
-  return(ERR_UNKNOWN);
+  return(ERR_AT_FAILED);
 }
 
 uint8_t ESP8266::join(const char* ssid, const char* password) {
   // set mode to station + soft AP
   if(!_mod->ATsendCommand("AT+CWMODE_CUR=3")) {
-    return(ERR_UNKNOWN);
+    return(ERR_AT_FAILED);
   }
   
   // reset the module
@@ -57,12 +57,12 @@ uint8_t ESP8266::join(const char* ssid, const char* password) {
   cmd += password;
   cmd += "\"";
   if(!_mod->ATsendCommand(cmd)) {
-    return(ERR_UNKNOWN);
+    return(ERR_AT_FAILED);
   }
   
   // disable multiple connection mode
   if(!_mod->ATsendCommand("AT+CIPMUX=0")) {
-    return(ERR_UNKNOWN);
+    return(ERR_AT_FAILED);
   }
   
   return(ERR_NONE);
@@ -204,12 +204,12 @@ uint8_t ESP8266::send(String data) {
   String cmd = "AT+CIPSEND=";
   cmd += data.length();
   if(!_mod->ATsendCommand(cmd)) {
-    return(ERR_UNKNOWN);
+    return(ERR_AT_FAILED);
   }
   
   // send data
   if(!_mod->ATsendCommand(data)) {
-    return(ERR_UNKNOWN);
+    return(ERR_AT_FAILED);
   }
   
   return(ERR_NONE);
@@ -238,14 +238,14 @@ uint8_t ESP8266::openTransportConnection(const char* host, const char* protocol,
   cmd += "\",";
   cmd += port;
   if(!_mod->ATsendCommand(cmd)) {
-    return(ERR_UNKNOWN);
+    return(ERR_AT_FAILED);
   }
   return(ERR_NONE);
 }
 
 uint8_t ESP8266::closeTransportConnection() {
   if(!_mod->ATsendCommand("AT+CIPCLOSE")) {
-    return(ERR_UNKNOWN);
+    return(ERR_AT_FAILED);
     }
   return(ERR_NONE);
 }
diff --git a/src/TypeDef.h b/src/TypeDef.h
index 6761aebf..c113e423 100644
--- a/src/TypeDef.h
+++ b/src/TypeDef.h
@@ -37,23 +37,25 @@
 // SX1278/SX1272 error codes
 #define ERR_CHIP_NOT_FOUND              0x01
 #define ERR_EEPROM_NOT_INITIALIZED      0x02
-#define ERR_PACKET_TOO_LONG             0x10
-#define ERR_RX_TIMEOUT                  0x20
-#define ERR_CRC_MISMATCH                0x21
-#define ERR_INVALID_BANDWIDTH           0x30
-#define ERR_INVALID_SPREADING_FACTOR    0x31
-#define ERR_INVALID_CODING_RATE         0x32
-#define ERR_INVALID_BIT_RANGE           0x40
+#define ERR_PACKET_TOO_LONG             0x03
+#define ERR_TX_TIMEOUT                  0x04
+#define ERR_RX_TIMEOUT                  0x05
+#define ERR_CRC_MISMATCH                0x06
+#define ERR_INVALID_BANDWIDTH           0x07
+#define ERR_INVALID_SPREADING_FACTOR    0x08
+#define ERR_INVALID_CODING_RATE         0x09
+#define ERR_INVALID_BIT_RANGE           0x10
 
 // ESP8266 error codes
-#define ERR_URL_MALFORMED               0x01
-#define ERR_RESPONSE_MALFORMED_AT       0x02
-#define ERR_RESPONSE_MALFORMED          0x03
+#define ERR_AT_FAILED                   0x01
+#define ERR_URL_MALFORMED               0x02
+#define ERR_RESPONSE_MALFORMED_AT       0x03
+#define ERR_RESPONSE_MALFORMED          0x04
 
 
 enum Slot {SlotA, SlotB};
 
-enum Bandwidth {BW_7_80_KHZ, BW_10_40_KHZ, BW_15_60_KHZ, BW_20_80_KHZ, BW_31_25_KHZ, BW_41_70_KHZ, BW_62_50_KHZ, BW_125_00_KHZ, BW_250_00_KHZ, BW_500_00_KHZ, };
+enum Bandwidth {BW_7_80_KHZ, BW_10_40_KHZ, BW_15_60_KHZ, BW_20_80_KHZ, BW_31_25_KHZ, BW_41_70_KHZ, BW_62_50_KHZ, BW_125_00_KHZ, BW_250_00_KHZ, BW_500_00_KHZ};
 enum SpreadingFactor {SF_6, SF_7, SF_8, SF_9, SF_10, SF_11, SF_12};
 enum CodingRate {CR_4_5, CR_4_6, CR_4_7, CR_4_8};