      {port}  => port number.
      example => ai/read/0
    */
-  {String("ai/read/"), &aiReadTask},
+  {"ai/read/", &aiReadTask},
 
   /*
     Switch AI reference volt.

     {val}   => write value.
     example => ao/write/1?val=100
   */
  {String("ao/write/"), &aoWriteTask},

  /*
     Read DI port.

     {type}   => INPUT | OUTPUT | INPUT_PULLUP
     example => d/mode/3?type=INPUT
   */
  {"d/mode/", &switchPinModeTask},

  /*
     Close serial port.
     format => system/close
   */
  {"system/close", &closeSerial}
};

void setup() {
