For cadence and speed, they are very rarely "wired" anymore. Almost all use ANT+ for communication, it's a very low power protocol meant for low power usage.
Electronic shifting (Other than SRAM's newest) is however wired, but again it's a very low power protocol. It also uses two motors to perform the shifts, but they are very small and external.
Electronic shifting (Other than SRAM's newest) is however wired, but again it's a very low power protocol. It also uses two motors to perform the shifts, but they are very small and external.
I would imagine you could tell the difference and find what you're looking for with something as simple as this: http://www.amazon.com/Fluke-LVD1-Volt-Light/dp/B000B64ZDG
I used to use one for electrical work, and it worked very well.