1) While most people on this forum know what a MAX232 is, most people also knows that there are many other chips with similar functionality. So RS232 is not equivalent with a MAX232. That is a reason why you should have mentioned the chip in your origianl post.

2) I have already explained that the MAX232 contains electronics that generates a negative voltage, since RS232 signalling makes use of a negative voltage. And I have already mentioned that the MAX232 chip needs a capacitor to buffer that negative voltage. It should then be obvious that if the MAX232 should store a negative voltage, it must do it in a capacitor that is "reversed".

3) What is mFd? mF = milli-farad = 1000 micro-farad = 1000 uF. The MAX232 does not use any 1000uF capacitors. As I mentioned, there are a lot of RS232 transceiver chips. Many of them use either 1uF or 0.1uF capacitors. There would not be a market for a chip that requirs 1000uF (1mF) capacitors since such capacitors would be more expensive and require a lot of extra space.