Different beacons transmit signals that vary in duration of repetition period, and pulse. This can cause for overlap of signals. Think of stopping at a traffic light in the turning lane and watching the blinker in front of you—although it had a consistent on and off pattern, this blinker will come in and out of sync with your blinker (varying in duration of repetition period and pulse). In the event of a multiple burial overlapping signals pose a potential confusing situation of picking up one or multiple signals. The PIEPS DSP models are able to figure out what other signals are nearby and then produce a completely separate signal, which does not overlap with the other signals nearby, thus clearly indicating to any searchers, the presence of two unique victims.
In The DSP and DSP Tour models the smart transmitter is consistently checking in with your group.
In the DSP Pro and DSP Sport the Smart Transmitter is activated by a lack of movement when the device is in send (transmit) mode.