Manual heartbeats are network licenses only and are implemented by default. You can send manual heartbeats by calling the API function LMX_Heartbeat() from your application.
Manual heartbeats work the same as automatic heartbeats, with the retry attempt count set to 1. However, when manual heartbeats fail, the HEARTBEAT_EXIT_FUNCTION is not called, as it would be if automatic heartbeats fail with a count set to 1.