so im going to be hooking up both a sirius tuner, and an ipod interface to the ip-bus. there is power hook up on the ipod interface, and then more power hook up on the sirius module. can i just wire up one or the other?? they have to be ponied together. so i figure if one ip-bus cable has power, than the other must too.

Both must be powered. You can daisy chain the power together though.

...can i just wire up one or the other?? they have to be ponied together. so i figure if one ip-bus cable has power, than the other must too.

Sure can...it should not be a problem. To be safe confirm what other equipment will be powered by the same line.