A non-addressable switch device that is part of a chain of switch devices in a gun string, the non-addressable switch device including a first switch configured to make an electrical connection between an electrical line and another non-addressable switch device of the chain of switch devices; a second switch configured to make an electrical connection between a detonator and the electrical line; and a processor PA connected to the first and second switches and configured to close and open the first and second switches. The processor PA is configured to not use a digital address, and the processor PA is configured to perform one of plural functions based on a corresponding pulse received along the electrical line.