Port Server TS4 reboot

I have question re Port Server rebooting . Is there any difference in the rebooting of a Port Server by a soft reboot by logging on via Digi Authority Remote software and initiating a reboot or by powering down.
We have had instances where the serial device connected to the Port Server will not reconnect if a soft reboot is initialized but will reconnect when the Port Server is power cycled.

Not aware of any differences in this regard between soft and hard reboots. What is connected to the serial ports? How are the attached devices connecting?