The purpose of these relay modules is to monitor remote host and to "keep it alive" based on ingoing/outgoins ICMP timeout.They monitors the availability of the LAN devices and automatically restarts them in case of failure. Unresponsive device (computer, router, switch, IP camera, WiFi AP...) is detected by unavailable no reply to PING. In such a case, the denkovi relay board can reset the device in order to get in back working.
Comparison table with differences between IP watchdog relays