If a top secret telephone calls a secret telephone, what is displayed on both devices?

When a top secret telephone engages in a call with a secret telephone, the classification displayed on both devices is "Top Secret." This is because in communication systems that are designed for classified information, the higher security classification takes precedence.

In this scenario, since one device is actively designated as top secret, it governs the communication standards and displays. The purpose of this classification hierarchy ensures that the most sensitive information maintains its integrity and is safeguarded, reflecting the higher classification rather than the lower one. By showing "Top Secret" on both devices, it emphasizes the need for heightened security awareness, ensuring that all personnel engaging in the conversation are cognizant of the sensitivity of the information being exchanged.

Other classifications, like "Classified," "Secret," or "Unclassified," would not accurately reflect the communication's sensitivity since none of these terms pertain to the higher classification level being utilized in this exchange.