I have some I/O with terminals designated as
i+
i-
iS

and another on with

i+
i-
iP

and another one
o+
o-

and I don't know what that means, if any one can help and give me any reference for what that might mean.
Thanks

 

Where do you see this: on a car? a power supply? signal generator? airplane? case packer?

At least give us a hint....much better chance of getting help !

 

these are the terminal designation for some kinds of IO cards for a brand called Foxboro.
For example for DI TA( termination assembly) the designation is:
iS, i+ and i-

For DO,
o+ and o- Or oK and oC

I did a search to know what is the standard behind this naming and failed