Type-ahead buffer overflow

   The 1k buffer in which commands are stored when previous commands are
   still active is full. The character causing the error is ignored. Two
   solutions are:
   - Wait until TV catches up. It is best not to continue typing, even if
     some space becomes available, until TV is interactively waiting for
     input once more.
   - Enter CTRL_G. This causes the current command to be aborted, and the
     type-ahead buffer is emptied.