What is the primary function of the heartbeat LED?

The heartbeat LED primarily serves to signal system activity. This indicator is designed to provide visual feedback regarding the operational status of the device. When the heartbeat LED is blinking or illuminated, it often means that the system is functioning properly and performing its processes as expected.

In a Verifone terminal, for instance, the heartbeat LED can assure users and technicians that the device is alive and operational, actively processing transactions or engaging in other essential functions. This function is crucial for smooth operations, especially in high-traffic environments where confirming the system's readiness and responsiveness is necessary.

The other options, while they may describe other functionalities of device indicators, do not accurately capture the primary purpose of the heartbeat LED, which is specifically linked to conveying the device's ongoing operational status.