Final answer:
Two-way communication systems are often required to be tested every six months, but it can vary by local regulations. Always refer to the pertinent safety codes and laws for specific maintenance intervals.
Step-by-step explanation:
The question pertains to the frequency at which two-way communication systems must be tested to ensure their proper functioning, which is commonly a safety protocol in various settings such as workplaces, schools, and public buildings. While the specific interval can vary by regulation, in many instances, the testing is required to be carried out at least every six months. It is important to refer to local laws and safety codes, as they provide detailed requirements for safety equipment maintenance, including communication systems.