Noob; Need Help w/ DS3231 RTC & Mega2560 - serial print is ASCII (??)

Serial monitor displays characters while executing sample code from various #include examples for this device.

The specific unit that I am using is

Connections are:
DS3231 ‘+’ goes to 5V on Mega
DS3231 ‘D’ goes to SDA (pin 20) on Mega
DS3231 ‘C’ goes to SCA (pin 21) on Mega
DS3231 ‘NC’ not used
DS3231 ‘-’ goes to GND on Mega

The

The code is

#include <Wire.h>
#include <RealTimeClockDS3231.h>

#define Display_Clock_Every_N_Seconds 1
#define Display_ShortHelp_Every_N_Seconds 25

int count=0;
char formatted[] = "00-00-00 00:00:00x";

void setup() {
//  Wire.begin();
  Serial.begin(115200);
}
 
void loop() {
  if(Serial.available())
  {
    processCommand();
  }
  delay(1000);
  RTC.readClock();
  count++;
  if(count % Display_Clock_Every_N_Seconds == 0){
    Serial.print(count);
    Serial.print(": ");
    RTC.getFormatted(formatted);
    Serial.print(formatted);
    Serial.println();
  }
  
  if(count % Display_ShortHelp_Every_N_Seconds == 0) {
    Serial.println("Send ? for a list of commands.");
  }

#ifdef TEST_1224Switch  
  if(count%10 == 0)
  {
    if(count %20 == 0)
    {
      Serial.println("switching to 12-hour time");
      RTC.switchTo12h();
      RTC.setClock();
    }
    else
    {
      Serial.println("switching to 24-hour time");
      RTC.switchTo24h();
      RTC.setClock();
    }
  }
#endif
}

void processCommand() {
  if(!Serial.available()) { return; }
  char command = Serial.read();
  int in,in2;
  switch(command)
  {
    case 'H':
    case 'h':
    in=SerialReadPosInt();
    RTC.setHours(in);
    RTC.setClock();
    Serial.print("Setting hours to ");
    Serial.println(in);
    break;
    case 'I':
    case 'i':
    in=SerialReadPosInt();
    RTC.setMinutes(in);
    RTC.setClock();
    Serial.print("Setting minutes to ");
    Serial.println(in);
    break;
    case 'S':
    case 's':
    in=SerialReadPosInt();
    RTC.setSeconds(in);
    RTC.setClock();
    Serial.print("Setting seconds to ");
    Serial.println(in);
    break;
    case 'Y':
    case 'y':
    in=SerialReadPosInt();
    RTC.setYear(in);
    RTC.setClock();
    Serial.print("Setting year to ");
    Serial.println(in);
    break;
    case 'M':
    case 'm':
    in=SerialReadPosInt();
    RTC.setMonth(in);
    RTC.setClock();
    Serial.print("Setting month to ");
    Serial.println(in);
    break;
    case 'D':
    case 'd':
    in=SerialReadPosInt();
    RTC.setDate(in);
    RTC.setClock();
    Serial.print("Setting date to ");
    Serial.println(in);
    break;
    case 'W':
    Serial.print("Day of week is ");
    Serial.println((int) RTC.getDayOfWeek());
    break;
    case 'w':
    in=SerialReadPosInt();
    RTC.setDayOfWeek(in);
    RTC.setClock();
    Serial.print("Setting day of week to ");
    Serial.println(in);
    break;
    
    case 't':
    case 'T':
    if(RTC.is12hour()) {
      RTC.switchTo24h();
      Serial.println("Switching to 24-hour clock.");
    } else {
      RTC.switchTo12h();
      Serial.println("Switching to 12-hour clock.");
    }
    RTC.setClock();
    break;
    
    case 'A':
    case 'a':
    if(RTC.is12hour()) {
      RTC.setAM();
      RTC.setClock();
      Serial.println("Set AM.");
    } else {
      Serial.println("(Set hours only in 24-hour mode.)");
    }
    break;
    
    case 'P':
    case 'p':
    if(RTC.is12hour()) {
      RTC.setPM();
      RTC.setClock();
      Serial.println("Set PM.");
    } else {
      Serial.println("(Set hours only in 24-hour mode.)");
    }
    break;
    
    case '>':
    in=SerialReadPosInt();
    in2=SerialReadPosInt();
    RTC.writeData(in, in2);
    Serial.print("Write to register ");
    Serial.print(in);
    Serial.print(" the value ");
    Serial.println(in2);
    break;    
    case '<':
    in=SerialReadPosInt();
    in2=RTC.readData(in);
    Serial.print("Read from register ");
    Serial.print(in);
    Serial.print(" the value ");
    Serial.println(in2);
    break;

    default:
    Serial.println("Unknown command. Try these:");
    Serial.println(" h## - set Hours       d## - set Date");
    Serial.println(" i## - set mInutes     m## - set Month");
    Serial.println(" s## - set Seconds     y## - set Year");
    Serial.println(" w## - set arbitrary day of Week");
    Serial.println(" t   - toggle 24-hour mode");
    Serial.println(" a   - set AM          p   - set PM");
    Serial.println();
    Serial.println(" z   - start clock     Z   - stop clock");
    Serial.println(" q   - SQW/OUT = 1Hz   Q   - stop SQW/OUT");
    Serial.println();
    Serial.println(" >##,###  - write to register ## the value ###");
    Serial.println(" <##      - read the value in register ##");
    
  }//switch on command
  
}

//read in numeric characters until something else
//or no more data is available on serial.
int SerialReadPosInt() {
  int i = 0;
  boolean done=false;
  while(Serial.available() && !done)
  {
    char c = Serial.read();
    if (c >= '0' && c <='9')
    {
      i = i * 10 + (c-'0');
    }
    else 
    {
      done = true;
    }
  }
  return i;
}

I have tested this on a genuine Arduino Mega 2560 and on an Elegoo Mega 2560. Both units successfully run other sketch’s (data logger using DS18B20 temp sensors, SD card shield etc.).
I have also tried two different DS3231 devices.

Any assistance is greatly appreciated.

Best regards,
Daryl

Is the serial monitor baud rate set to 115200?