If the keyboard quits typing then there are two possible solutions that may fix the problem.
Both of these solutions have to do with the "BlackBox" media extender. If you follow the keyboard
wire back to its plug then you will find this box.

• Try unplugging the keyboard for a period of a few seconds.

Or if that does not work..

• Try disconnecting and then reconnecting the power cord to the "BlackBox" extender.

If that does not work...

• Check the white CAT5  cables into the black box. It is likely that one of these is loose
  especially if one of the monitors has gone blank.