[Nut-upsuser] Can anyone give me some ideas?

[nick]

I've got a big UPS from an italian manufacturer MSC elettronica which 
should be megatec protocol based. They distribute it with Upsilon2000, 
developed by Megatec, and with a cable listed on the megatec site:

http://www.megatec.com.tw/FAQ.htm

How do I know the M2505 cable is the one that should be used on my UPS 
instead of M2502 cable?

UPS that use both these cables are TRUE RS232 UPS with MegaTec protocol. 
  The difference is:

UPS communicate with computer on pin 6.7.9 ---> M2502 cable
UPS communicate with computer on pin 2.3.5 ---> M2505 cable

UPS listed below are the ones who uses M2505 cable:

Delta: GES-N
Chroma: 91 Series
Phoenixtec: C Series


So, as far as I can tell, it should be using the megatec driver, but I'm 
not sure if there's something I need to change or specify to let it know 
  that the signaling pins are 2.3.5, or if in fact there's another 
better adapted driver in this case?

I also have a dumb port that I can fall back on, but I'd prefer a bit 
more information if at all possible.

I'm using CentOS 5.0, with nut 2.2.0, and ttyS0 is the only serial port 
I have available on the machine.

  setserial -g /dev/ttyS0
/dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4

The cable is good and no one is using the serial port (at least I never 
receive any indication of this).

Can anyone give me an idea of where to look or try next?

Nick