But intercoms have like everything else joined the digital age, so those two wires now carry a load of other functionality as digital signalling. [Aaron Christophel] installs these devices for a ...

The fundamental concept to understand about two-wire technology is that devices using it are powered by and communicate with the same two wires in a loop. This is why two-wire technology is often ...

For a 6 wire device, the extra two wires are center taps and a 5 wire motor will have both center taps tied together. Measuring resistance between two wires should give you one of three readings.