3+1, 3+2, 4+1, and 4+2 are examples of _____.

The correct answer identifies 3+1, 3+2, 4+1, and 4+2 as communication formats supported by alarm panels. These notations refer to specific configurations used in alarm systems, particularly in specifying the way signals are structured or communicated between the various components of an intrusion detection system.

In the context of alarm panels, these formats indicate how many zones (or circuits) a particular panel can monitor and the various signal types it can support. For example, the numbers can denote the number of alarm zones and auxiliary features, helping to elucidate the panel's capability. This is crucial for system designers and operators to understand, as it affects how they set up and manage alarm systems.

Choosing this option highlights how communication protocols in alarm systems are designed to handle different scenarios based on the number of zones and configurations, directly impacting their effectiveness and functionality. The understanding of these formats is essential for integrating alarm systems within a broader security architecture.