If you want to the run an external siren or audible device with TR4030/TR4050 to advise the time of start/break/finish

TR4030/TR4050 has two internal relays at the bottom of it (see the picture as below). One is for the bell, the other is for the lock. Connect your external siren or audible device with “the relay for bell”. Then see If you want to set "Bell Table" to set the bell time.