Adafruit Fona, SMS receive, Teensy 3.2

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Hi,

I read a lot here and now it is time for my first post I hope I do it right.

I attached an Adafruit Fona board to my Teensy 3.2. Works fine so far. I can send SMS and retrieve them. The demo from Adafruit works fine.

Only one problem is there (at the moment), I fixed it, but I would like to know why it is there.

This is the code I'm testing:

  void loop() {
    
    char* bufPtr = fonaInBuffer; //handy buffer pointer
    
    if (fona.available()) //any data available from the FONA?
    {
      int slot = 0; //this will be the slot number of the SMS
      int charCount = 0;
      //Read the notification into fonaInBuffer
      do {
        *bufPtr = fona.read();
        Serial.write(*bufPtr);
        delay(1);
      } while ((*bufPtr++ != '\n') && (fona.available()) && (++charCount < (sizeof(fonaInBuffer)-1)));
      
      //Add a terminal NULL to the notification string
      *bufPtr = 0;
      
      //Scan the notification string for an SMS received notification.
      // If it's an SMS message, we'll get the slot number in 'slot'
      if (1 == sscanf(fonaInBuffer, "+CMTI: \"SM\",%d", &slot)) {
        Serial.print("slot: "); Serial.println(slot);
        
        char callerIDbuffer[32]; //we'll store the SMS sender number in here
        
        // Retrieve SMS sender address/phone number.
        if (! fona.getSMSSender(slot, callerIDbuffer, 31)) {
          Serial.println("Didn't find SMS message in slot!");
        }
        Serial.print(F("FROM: ")); Serial.println(callerIDbuffer);
        
        //Send back an automatic response
        Serial.println("Sending reponse...");
        if (!fona.sendSMS(callerIDbuffer, "Hey, I got your text!")) {
          Serial.println(F("Failed"));
        } else {
          Serial.println(F("Sent!"));
        }
        
        // delete the original msg after it is processed
        // otherwise, we will fill up all the slots
        // and then we won't be able to receive SMS anymore
        if (fona.deleteSMS(slot)) {
          Serial.println(F("OK!"));
        } else {
          Serial.println(F("Couldn't delete"));
        }
      }
    }
  }

The interesting part for my problem is:

if (1 == sscanf(fonaNotificationBuffer, "+CMTI: " FONA_PREF_SMS_STORAGE ",%d", &slot)) {

The format string for sscanf never worked until I changed it to:

if (1 == sscanf(fonaNotificationBuffer, "%*c%*c+CMTI: " FONA_PREF_SMS_STORAGE ",%d", &slot)) {

The char buffer filled with fona.read() contains a hex D and hex A in front of the "+CMTI: \"SM\",n" and I wonder why do I have them there? I found no sample with a modified format for sscanf - so why do I have this problem and others don't?!

Thanks!