On Thursday, November 27, 2014 6:21:37 AM UTC-8, Maynard A. Philbrook Jr. wrote:
The more I think about it, being a tablet and all, I would bet that
it's the connector for the docking station.

The photo now shows the cover as well as the connector.
http://carnot.yi.org/TatungTWN5213RS232.png

Also the machine is illustrated here.
http://www.akori.fr/webpad_galerie.html
RS232 is marked.

The peculiar "odd connector-DE9 subminiature" is in this picture.
http://www.akori.fr/webpad_solutions.html

No doubt the function is RS232. I only wonder who made the connector.

Thanks for the replies, ... Peter E.