According to an aspect, there is provided an elevator communication system. The system comprises an ethernet bus, a safety master node communicatively connected to the ethernet bus and configured to communicate via the ethernet bus, and safety slave nodes communicatively connected to the ethernet bus and configured to communicate via the ethernet bus. The safety master node and the safety slave nodes are configured to communicate by using a time-triggered communication protocol. In the time-triggered communication protocol the safety master node is configured to send a polling diagnostic request message to the safety slave nodes by using a predetermined polling cycle.