rtx/rtxModem.py

# -*- coding: UTF-8 -*-
'''
rtx - RetroText
rtxModem: Modem-Funktionen
by Anna Christina Naß <acn@acn.wtf>
released under GPL
'''

import glob
import serial
import config
import logging

def init_modem():
    logging.debug("clearing input/output buffers")
    glob.ser.reset_input_buffer()
    glob.ser.reset_output_buffer()
    """ send the modem init strings to the modem """
    logging.debug("init_modem")
    if config.MODEM_INIT1 != "":
        logging.debug("sending MODEM_INIT1")
        glob.ser.write(bytes(config.MODEM_INIT1 + "\r", "latin-1"))
        rc = _serial_readline()
        logging.info("MODEM_INIT1: %s", rc)
        rc = _serial_readline()
        logging.info("MODEM_INIT1: %s", rc)

    if config.MODEM_INIT2 != "":
        logging.debug("sending MODEM_INIT2")
        glob.ser.write(bytes(config.MODEM_INIT2 + "\r", "latin-1"))
        rc = _serial_readline()
        logging.info("MODEM_INIT2: %s", rc)
        rc = _serial_readline()
        logging.info("MODEM_INIT2: %s", rc)

def wait_for_caller():
    """ waits for the RING of the modem and answers it """
    modem_answered = False
    logging.debug("wait_for_caller")
    while not modem_answered:
        rc = _serial_readline()
        if rc.startswith(config.MODEM_RING):
            logging.info("modem ringing! Answering.")
            glob.ser.write(bytes(config.MODEM_ANSWER + "\r", "latin-1"))
            rc = _serial_readline()
            logging.info("Answer: %s", rc)
            rc = _serial_readline()
            logging.info("Answer: %s", rc)
            modem_answered=True
        else:
            modem_answered=False

def _serial_readline():
    line = ""
    in_byte = ""
    
    while not in_byte == b"\n":
        in_byte = glob.ser.read(1)
        #print(in_byte)
        line += str(in_byte, encoding="latin-1")

    return line