the older generation iPods and iPhones are not compatible with the new 30-pin dock connectors and vice versa.
You've probably bought an obsolete version of Monster cable which is not compatible with your nano? What generation nano do you have?
The cables usually tell you which generation they are compatible with.
Can you post the model of both the nano and the cable?
I've had the same problem - have a monster cable 12v transmitter which is now junk, because starting with iPod classic 5 g and onward, it is incompatible with anything else. Same goes for touch.
Thanks for the info. My Monster cable is very old; I had been using it with my original iPod. You have verified for me that I will need to purchase an updated cable. btw, I already had to buy a new Mac because my G4 wouldn't support the iTunes version necessary for the Nano. Despite the difficulties that changing technology causes I do love what it can do :]