Ethernet NTP digital wall clocks plug into an NTP times server using an Ethernet cable. This means that the time signal is sent from the NTP time server directly to the Ethernet NTP digital wall clock, maintaining its accuracy. The Ethernet digital wall clock never needs setting as it is automatically set by the time signal sent from the times server, which means it will always be accurate, and the Ethernet NTP digital wall clock requires no mains power or batteries as it gets its power form the Ethernet.
NTP POE wall clocks use Network Time Protocol (NTP) to maintain accuracy and synchronisation. NTP is a computer algorithm that works by taking a single master time source that it distributes to all devices on a network. In the case of most NTP systems, the time is received via a NTP time server that is hooked up to a computer network.