import string
import serial
import time

port = serial.Serial(port='COM3', baudrate=2400, bytesize=8, parity='N', stopbits=1)

for c in string.ascii_uppercase:
    for n in range(100):
        d = c+f"{n:02d}"
        port.write((d+chr(13)).encode())
        port.flush()
        r = port.read_all().decode('ascii').rstrip()
        print(f"{d} : {r}", sep='^H')
        if 'NAK' not in r:
            print()
        time.sleep(0.1)