Managing slave devices

A hardware system comprises a digital signal generator, which generates a digital electrical signal that describes a first physical state of a first device; an analog electrical signal generator, which generates an analog electrical signal that describes a second physical state of the first device; a hybrid digital state signal generator, which generates a hybrid digital state signal that comprises the analog electrical signal overlaid onto the initial digital electric signal; and a hybrid signal transmitter, which transmits the hybrid digital state signal from the first device to a second device, wherein the second device comprises a hybrid signal receiver/decoder that extracts the analog electrical signal from the hybrid digital state signal.