2011/11/21 <ml...@nocturnal.org>: > I'm working on a project where I need to communicate with some devices via > modem which have the possibility of using MARK and SPACE parity. These are > not defined by POSIX and therefore are not directly supported under Linux. > > I've found the following discussion on the topic: > > http://www.lothosoft.ch/thomas/libmip/markspaceparity.php > > and I have been trying to use this information (since the TERMIOS module is > available) to proceed with the communication. > > I was able to use minicom to determine that the first device I started > testing with uses 7M1 but cannot figure out how to implement the solution > described by the author above. >
"The modes 7M1 (7 data bits, MARK parity, 1 stop bit) and 7S1 (7 data bits, SPACE parity, 1 stop bit) can easily be emulated using 8N1 (0 data bits, NO parity, 1 stop bit) and setting the 8th data bit to 1 resp. 0. This is relatively simple to implement and cannot be distinguished by the receiver." It means that 7M1 === 8N1. Set 8N1 mode on your side and 7M1 on the other side. I really do not understand what is the reason to have dedicated 7M1 or 7S1 mode - it is no different from regular 8 bit mode from the hardware point of view. From the software point of view it is just the matter of the definition of the highest bit. In other words, 7M1/7S1 are two complementary subsets of a single 8N1 set. HTH -- http://mail.python.org/mailman/listinfo/python-list
