Okay, I think this is for updates.
added Reset switch.
deleted autopower, added 3-pin jumper field (5V from regulator, 5V from USB).
(user can bring the three pins to a panel mount toggle/rocker if desired, or to bring in external 5V).
added DS1307 RTC, crystal, pullups for Square wave output, SCL, SDA lines.
added 20mm coincell battery, on Bottom of the board.
RS232 remains. 3 pin header with Gnd in middle for easy board-to-board connections, or to offboard DSub connector.
Both SD & MicroSD remain, up to builder to populate desired socket.
ICSP header.
JTAG header.
Question: How do I get the battery holder markings to show up on the bottom of the board?
And will what I presume is a plastic coin cell battery holder be interfered with by the atmega socket pins ? If so I need to adjust it placement and fix the routing around it.
Any other options/features/requests?