Aspects of the present disclosure provide non-addressable detection and alarm systems and methods for controlling a combined circuit by a control panel. In an example, a combined circuit may include paired wires, one or more initiating devices, and one or more notification appliances communicatively coupled with the paired wires in parallel. The control panel may monitor the one or more initiating devices in a standby mode while maintaining the one or more notification appliances in an off state. When the control panel detects an anomaly from one or more initiating devices, the control panel may switch the combined circuit to an alarm mode. In the alarm mode, the control panel may activate the one or more notification appliances and maintain the one or more initiating devices in an off state.