I found a strange communications bug yesterday, all communication stop when the following conditions are met
1) Software fitted with X-Lock ( X-Lock will be displayed in the LCD on power-up or reset)
2) Running timecode connected to the reader
3) Machine reporting a different standard connected to the port
If you think that you encounter this bug
Check the device name displayed in the faulty port, if the standard is different to the system standard then the standard letter will be added (P(25), N(Non-Drop), F(24), D(Drop). If yes try disconnecting the timecode connected to the reader input, or Hard Reset (SR-4: [<<] + [Locate], RM-6: [Clear] + [Shift]).
I have fixed this bug on software from October 2010