libphonenumber\PhoneNumberUtil::initDiallableCharMappings PHP Method

    protected static function initDiallableCharMappings()
    {
        static::$DIALLABLE_CHAR_MAPPINGS = static::$asciiDigitMappings;
        static::$DIALLABLE_CHAR_MAPPINGS[static::PLUS_SIGN] = static::PLUS_SIGN;
        static::$DIALLABLE_CHAR_MAPPINGS['*'] = '*';
        static::$DIALLABLE_CHAR_MAPPINGS['#'] = '#';
    }