diff --git a/firmware/command_config.h b/firmware/command_config.h
index 9274a55..eba75b8 100755
--- a/firmware/command_config.h
+++ b/firmware/command_config.h
@@ -24,24 +24,28 @@
 
 void cc_setBaudrate(void);
 void cc_getBaudrate(void);
+void cc_setMuxLine(void);
 void cc_startBootloader(void);
 
 /*****************************************************************************/
 
 #define CC_CMD_SET_BAUDRATE   0x0A
 #define CC_CMD_GET_BAUDRATE   0x14
+#define CC_CMD_SET_MUX_LINE   0x1E
 #define CC_CMD_START_BTLDR    0x32
 
 /*****************************************************************************/
 
 #define CC_CMD_SET_BAUDRATE_FUNC   &cc_setBaudrate
 #define CC_CMD_GET_BAUDRATE_FUNC   &cc_getBaudrate
+#define CC_CMD_SET_MUX_LINE_FUNC   &cc_setMuxLine
 #define CC_CMD_START_BTLDR_FUNC    &cc_startBootloader
 
 /*****************************************************************************/
 
 #define CC_CMD_SET_BAUDRATE_DATA_TO_READ  4 // set baudrate
 #define CC_CMD_GET_BAUDRATE_DATA_TO_READ  0 // get baudrate
+#define CC_CMD_SET_MUX_LINE_DATA_TO_READ  1 // set mux line
 #define CC_CMD_START_BTLDR_DATA_TO_READ   0 // start bootloader
 
 /*****************************************************************************/
@@ -53,18 +57,21 @@ void cc_startBootloader(void);
 uint8_t cc_commands[] = { 
     CC_CMD_SET_BAUDRATE,
     CC_CMD_GET_BAUDRATE,
+    CC_CMD_SET_MUX_LINE,
     CC_CMD_START_BTLDR,
   };
 
 void (*cc_cmd_functions[])() = {
     CC_CMD_SET_BAUDRATE_FUNC,
     CC_CMD_GET_BAUDRATE_FUNC,
+    CC_CMD_SET_MUX_LINE_FUNC,
     CC_CMD_START_BTLDR_FUNC,
   };
 
 uint8_t cc_cmd_data_to_read[] = {
      CC_CMD_SET_BAUDRATE_DATA_TO_READ,
      CC_CMD_GET_BAUDRATE_DATA_TO_READ,
+     CC_CMD_SET_MUX_LINE_DATA_TO_READ,
      CC_CMD_START_BTLDR_DATA_TO_READ,
   };
 
diff --git a/firmware/command_functions.c b/firmware/command_functions.c
index 644e91d..034a929 100755
--- a/firmware/command_functions.c
+++ b/firmware/command_functions.c
@@ -60,3 +60,47 @@ void cc_startBootloader()
 
 /*****************************************************************************/
 
+void cc_setMuxLine()
+{
+  switch(cc_read_data[0])
+  {
+    case 0:;
+      EN_MUX_LINE0;
+      break;
+    case 1:;
+      EN_MUX_LINE1;
+      break;
+    case 2:;
+      EN_MUX_LINE2;
+      break;
+    case 3:;
+      EN_MUX_LINE3;
+      break;
+    case 4:;
+      EN_MUX_LINE4;
+      break;
+    case 5:;
+      EN_MUX_LINE5;
+      break;
+    case 6:;
+      EN_MUX_LINE6;
+      break;
+    case 7:;
+      EN_MUX_LINE7;
+      break;
+    default:;
+      EN_MUX_LINE0;
+      char* sBody = "     ";
+      sprintf(sBody, "%c%c%c%c%c", MSG_SOM1, MSG_SOM2, MSG_TYPE_ANSWER_NOK, MSG_EOM1, MSG_EOM2);
+      USB_serialStreamWriteC(sBody, strlen(sBody));
+      return;
+
+  }
+
+  char* sBody = "     ";
+  sprintf(sBody, "%c%c%c%c%c", MSG_SOM1, MSG_SOM2, MSG_TYPE_ANSWER_OK, MSG_EOM1, MSG_EOM2);
+  USB_serialStreamWriteC(sBody, strlen(sBody));
+}
+
+/*****************************************************************************/
+
diff --git a/firmware/globals.h b/firmware/globals.h
index 775c253..fd28d7b 100755
--- a/firmware/globals.h
+++ b/firmware/globals.h
@@ -11,5 +11,47 @@
     #define MSG_TYPE_ANSWER_NOK 0x02
     #define MSG_TYPE_BAUDRATE   0x03
 
+/*****************************************************************************/
+
+    #define EN_MUX_LINE0     \
+      PORTB &= ~(1 << PIN4); \
+      PORTB &= ~(1 << PIN5); \
+      PORTB &= ~(1 << PIN6); \
+
+    #define EN_MUX_LINE1     \
+      PORTB &= ~(1 << PIN4); \
+      PORTB &= ~(1 << PIN5); \
+      PORTB |=  (1 << PIN6); \
+
+    #define EN_MUX_LINE2     \
+      PORTB &= ~(1 << PIN4); \
+      PORTB |=  (1 << PIN5); \
+      PORTB &= ~(1 << PIN6); \
+
+    #define EN_MUX_LINE3     \
+      PORTB &= ~(1 << PIN4); \
+      PORTB |=  (1 << PIN5); \
+      PORTB |=  (1 << PIN6); \
+
+    #define EN_MUX_LINE4     \
+      PORTB |=  (1 << PIN4); \
+      PORTB &= ~(1 << PIN5); \
+      PORTB &= ~(1 << PIN6); \
+
+    #define EN_MUX_LINE5     \
+      PORTB |=  (1 << PIN4); \
+      PORTB &= ~(1 << PIN5); \
+      PORTB |=  (1 << PIN6); \
+
+    #define EN_MUX_LINE6     \
+      PORTB |=  (1 << PIN4); \
+      PORTB |=  (1 << PIN5); \
+      PORTB &= ~(1 << PIN6); \
+
+    #define EN_MUX_LINE7     \
+      PORTB |=  (1 << PIN4); \
+      PORTB |=  (1 << PIN5); \
+      PORTB |=  (1 << PIN6); \
+
 /*****************************************************************************/
 
diff --git a/firmware/main.c b/firmware/main.c
index 3a107f7..9a8334b 100755
--- a/firmware/main.c
+++ b/firmware/main.c
@@ -126,6 +126,11 @@ void SetupHardware(void)
   PMIC.CTRL = PMIC_LOLVLEN_bm | PMIC_MEDLVLEN_bm | PMIC_HILVLEN_bm;
 #endif
 
+  // set the three MUX control lines to output
+  DDRB  |= (1 << PIN4) | (1 << PIN5) | (1 << PIN6);
+  // set every pin to low
+  EN_MUX_LINE0;
+
   /* UART Hardware Initialization */
   uart_init( UART_BAUD_SELECT(baudrate, F_CPU) );