Patent ID: 8884778

Claim:
A method of communicating with a switch unit located on a perforating gun, release device, or explosive device for lowering into a wellbore comprising the steps of: sending a command to the switch unit; identifying the status of a switch with a state machine within the switch unit; identifying one or more valid commands for the status of the switch with the state machine; determining whether the command is valid for the status of the switch with the state machine; if the command is invalid, returning a signal comprising an error message from the switch unit at a current level in the range of from about 4 milliamps to about 15 milliamps; if the command is valid, controlling the position of the switch; and if the command is valid, returning a signal validating switch status from the switch unit at a current level in the range of from about 4 milliamps to about 15 milliamps.