only a couple of components are on the board - the ICs are a SARONIX RTC58321B and a SN7400N
A-Time remains active until the clock is read (by issuing the Read-RTC program from CLI or the Startup-Sequence), after that it becomes inactive and the parallel port is passed through transparently
without Read-RTC it will be automatically disabled when output is detected (eg. towards a printer)
when inactive, it's not possible to read or set the clock until the next reset or startup
early versions were hanging down from the parallel port, conflicting with the A1300 genlocks so later it was changed to hang upturned