Type          : 53
 Name          : Toggle "Do not disturb"
 Optional Data : None

   This  another  multi-line feature only.  It allows the  user
   turn  on or off the ability of other users to  send  him/her
   messages  whith  the type 54 function,  like - "Hey  Joe,  I
   noticed  that you're on line 3.  Wanna chat?" Note that  the
   sysop  has the ability to override this and send  a  message
   anyway.