Converting string of bytes to integer

General Usage
4

I got this working by rewriting the function as given below:

function analogRead(file_des::SerialPorts.SerialPort , pin_no::Int64)
  str = "A"*string(Char(48+pin_no))   #"An" for analog value on pin n
  write(file_des,str)
  sleep(0.1)                          # Delay next step by 100 milliseconds
  n = bytesavailable(file_des)          # Get number of bytes in input buffer
  s = read(file_des, n)                # Read n bytes from SerialPort
  iolit = IOBuffer(s) 
  num = read(iolit, Int16)
  # println(sizeof(num))
  # println(num[1])
  # @printf("value = %d", Int(num))
  close(iolit)
  
  # typeof(s) 
  # k = parse(Int,s)                    # Convert String to integer
  return num                           # Return the integer
end

Thank you, @Benny, for your response.