Last night i stumbled apon a feature in the 3100D that displayed these settings

:RS232 MODE:
01 Disabled
02 External X-Crypt
03 Master RS232 Sharing
04 Slave RS232 Sharing
05 RS232 Master + Slave
06 IP Master Receiver

Now i'm pretty sure that 03-05 are used for box to box fireware update? not quite sure if i'm correct i apologize if i'm wrong but i have no idea what the last and 2nd options are. Could they be Cardsharing options?