OldSynths

hi all,
i have a moog source with a control voltage input (CV), but i'm not 
really familiar with what it does and how it works.
i understand you can feed a signal in to the CV input, and somehow 
control the synth.

what kind of signal should be fed in to the CV-input(any audio 
signal??), and which parameters(pitch only??) are controllable with 
the signal?

thanks for any help!

/einar