     if (top < sizeof stack)
       stack[top++] = value;
     value = 0;
-  } else if ('a' <= c && c <='z') {
+  } else if (('a' <= c && c <='z') || (c =='+')) {
     Serial.print("> ");
     for (byte i = 0; i < top; ++i) {
       Serial.print((int) stack[i]);

        value = bandToFreq(value);
        if (value) {
         config.nodeId = (value << 6) + (config.nodeId & 0x3F);
         config.frequency = 351;
         rf12_control(0xA000 + config.frequency); 
         saveConfig();
        } else {
            showHelp();
        }
        break;
      case 'o': // set frequency
//                                                           // inc[4] = { 0, 120, 60, 40 }; // to change frequency by 0.3 MHz      
         if (value) {
          Serial.print(config.frequency);
          config.frequency = config.frequency + value;       // 96 - 3960 is the range of values supported by the RFM12B
          Serial.print("->");
          Serial.print(config.frequency);
          rf12_control(0xA000 + config.frequency); 

  static byte bands[4] = { 15, 30, 60, 0 }; // 315, 433, 864, 915 Mhz    // 96 - 3960 is the range of values supported by the RFM12B
  band = config.nodeId >> 6;
  addInt(config.msg, FreqFromBand(band)); // Store high order digit of frequency
  unsigned long freq = bands[band];
                                                   Serial.println(freq);
                                                   Serial.println(config.frequency);
  freq = freq * 100;
                                                   Serial.println(freq);
  unsigned long wk = config.frequency;                
                                                   Serial.println(wk);
  wk = wk * (band * 25);
  wk = wk / 100;
                                                   Serial.println(wk);
  freq = freq + wk;
                                                   Serial.println(freq);
 ////////////////////////////////
   unsigned long characteristic = freq/100;
                                                   Serial.println(characteristic);
  if (characteristic < 10)
    strcat(config.msg, "x");
  if (characteristic == 0)
    strcat(config.msg, "z");
  addInt(config.msg, characteristic);
  strcat(config.msg, ".");
  addInt(config.msg, (freq - (characteristic * 100)));
                                                   Serial.println(sizeof config.msg);
  strcat(config.msg, " MHz");
  
  config.crc = ~0;
  for (byte i = 0; i < sizeof config - 2; ++i)
