diff --git a/src/cw.cpp b/src/cw.cpp
new file mode 100644
index 0000000..881f453
--- /dev/null
+++ b/src/cw.cpp
@@ -0,0 +1,37 @@
+#include <Arduino.h>
+#include <ctype.h>
+
+uint8_t convertASCII(char c){
+    uint8_t result;
+    if(isalpha(c)){
+        if(islower(c)){
+            result = (uint8_t)c - 97;
+        }else{
+            result = (uint8_t)c - 65;
+        }
+    } else if (isdigit(c)){
+        result = (uint8_t)c - 22;
+    } else {
+        switch (c) {
+        case '-':
+            result = 36;
+            break;
+        case '.':
+            result = 36;
+            break;
+        case ',':
+            result = 36;
+            break;
+        case '?':
+            result = 36;
+            break;
+        case '/' || '\\':
+            result = 36;
+            break;
+        default:
+            result = 41;
+            break;
+        }
+    }
+    return result;
+}
\ No newline at end of file
diff --git a/src/cw.h b/src/cw.h
new file mode 100644
index 0000000..ee028a8
--- /dev/null
+++ b/src/cw.h
@@ -0,0 +1,55 @@
+#ifndef CW_H
+#define CW_H
+
+#include <Arduino.h>
+#include <ctype.h>
+
+// Morse code representation for each character (A-Z, 0-9)
+const char* morseCode[42] = {
+    ".-",    // A
+    "-...",  // B
+    "-.-.",  // C
+    "-..",   // D
+    ".",     // E
+    "..-.",  // F
+    "--.",   // G
+    "....",  // H
+    "..",    // I
+    ".---",  // J
+    "-.-",   // K
+    ".-..",  // L
+    "--",    // M
+    "-.",    // N
+    "---",   // O
+    ".--.",  // P
+    "--.-",  // Q
+    ".-.",   // R
+    "...",   // S
+    "-",     // T
+    "..-",   // U
+    "...-",  // V
+    ".--",   // W
+    "-..-",  // X
+    "-.--",  // Y
+    "--..",  // Z
+    "-----", // 0
+    ".----", // 1
+    "..---", // 2
+    "...--", // 3
+    "....-", // 4
+    ".....", // 5
+    "-....", // 6
+    "--...", // 7
+    "---..", // 8
+    "----.", // 9
+    "-...-",  // -
+    ".-.-.-", // .
+    "--..--", // ,
+    "..--..", // ?
+    "-..-.",  // /
+    ".-.-.",  // End Of Message (41)
+};
+uint8_t convertASCII(char c);
+const char* allowedCharacters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-.,?/\\";
+
+#endif // CW_H
\ No newline at end of file
diff --git a/src/main.cpp b/src/main.cpp
index 0a7a2bf..0be45c4 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -14,6 +14,7 @@
 
 #include <Arduino.h>
 #include <EEPROM.h>
+#include "cw.h"
 
 /* TODO:
  * - Implement sending strings
@@ -29,6 +30,7 @@ uint16_t p_tol = 10, p_min = 50, p_max = 2000, p_buf = 0, p_cache = 0;
 String serial_buffer = "";
 char buf;
 
+void key_string(String);
 void adjust_length(uint16_t);
 void set_length(uint16_t, uint16_t);
 void send(bool);
@@ -42,11 +44,11 @@ void setup() {
   pinMode(input_dah, INPUT_PULLUP);
   pinMode(input_pot, INPUT);
   pinMode(output, OUTPUT);
-  digitalWrite(output, HIGH);
+  digitalWrite(output, LOW);
   log("Read EEPROM\n");
   dit = EEPROM.read(20);
   dah = EEPROM.read(21);
-  // debug = EEPROM.read(22);
+  debug = EEPROM.read(22);
   p_buf = analogRead(input_pot);
   adjust_length(p_buf);
   log("Setup complete\n");
@@ -62,7 +64,6 @@ void setup() {
 }
 
 void loop() {
-  log(".");
   if (!digitalRead(input_dah)){
     send(true);
   }else if (!digitalRead(input_dit)){
@@ -82,13 +83,10 @@ void loop() {
 
   if (Serial.available() > 0) {
     buf = Serial.read();
-    log("SR ");
-    log(String(buf));
-    log("\n");
     if ((uint16_t) buf == 13){
       process_input(serial_buffer);
       serial_buffer = "";
-    } else {
+    } else if ((uint8_t) buf > 27 ){
       serial_buffer += buf;
     }
   }
@@ -111,7 +109,7 @@ void process_input(String input){
   log(input);
   log("\n");
   char command = input[0];
-  input.remove(0);
+  input.remove(0,1);
   log("Command: ");
   log(String(command));
   log(" - ");
@@ -120,7 +118,7 @@ void process_input(String input){
   uint16_t length = 0;
   switch(command){
   case 'S':
-    // TODO
+    key_string(input);
     break;
   case 'I':
     length = input.toInt();
@@ -132,6 +130,7 @@ void process_input(String input){
     break;
   case 'D':
     debug = boolean(input.toInt()==1);
+    log("Debug mode enabled");
     EEPROM.write(22, debug);
     break;
   default:
@@ -140,13 +139,39 @@ void process_input(String input){
   }
 }
 
+void key_string(String input){
+  // log("Sending string: ");
+  // log(input);
+  // log("\n");
+  uint8_t b = 0; 
+  for (uint8_t i = 0; i < input.length(); i++){
+    char c = input[i];
+    if ((uint8_t)c != 32){
+      b = convertASCII(c);
+      for(uint8_t y = 0; y < strlen(morseCode[b]); y++){
+        send(morseCode[b][y] == '.');
+        delay(dit);
+      }
+      if(debug){
+        Serial.print(' ');
+      }
+      delay(dit);
+    } else {
+      if (debug){
+        Serial.print(" ");
+      }
+      delay(dah);
+    }
+  }
+}
+
 void send(bool b) {
-  log("Sending ");
-  log(b?"dah":"dit");
-  log("\n");
-  digitalWrite(output, LOW);
-  delay(b?dit:dah);
+  if (debug){
+    Serial.print(b?"+":"=");
+  }
   digitalWrite(output, HIGH);
+  delay(b?dit:dah);
+  digitalWrite(output, LOW);
 }
 
 void set_length(uint16_t length_dit, uint16_t length_dah) {