Our WiFi bell systems use a time and attendance clock connected by WiFi to your network. They then connect by simple two wire cable to each bell.
Linortek clocks can be delivered wired, or with an integrated bell or horn.
Linortek controllers are connected by wire to your network, and get the time from then NTSP servers, or your network server - your choice.
Pyramid Wireless systems can transmit the time to digital and analog clocks, but the bells have to be wired to the controller.