Crosstalk or "leakage" occurs when the instrument's magnetic pickups receive the signal from rotating metal tonewheels other than those selected by the organist.
When the communication distances exceed few millimeters, optical interconnects provide advantage over the electronic interconnects in term of power, speed and crosstalk property.
The term "noise" usually means an undesirable random disturbance, but is often extended to include unwanted signals conflicting with the desired signal (such as crosstalk).