Hi,
Resectfully, the informations couldn't be more vague.
"An instrument" --> could be anything. Read it's datasheet. If you don't understand the given information, then please provide a link to the datasheet and tell us what is unclear.
"A cable" --> most probably the cable is connected to some device. We don't know. You have to tell us. A pure cable has no pins at all, thus I guess there is a connector. Maybe a standard connector, maybe some custom connector. Please give more detailed information. Regarding datasheet: here applies the same as above.
A signal" --> could be anything. Analog, digital, modulated, single ended, differential .... we need more information. It could be audio, it could be an antenna signal, it could be USB, it could be the diagnosis signals of your car. All need different treatment.
Not meant offending, just to give you a picture:
Pin numbers without context have no meaning. It's like saying the train stops at platform 12. Not knowing which station, nor time nor if you want to enter or leave the train.
Klaus