Taken from the man page (ntip.1):
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     Ntip differs from the traditional tip in a number of ways:

     1.   It does not support calling a remote system, all auto-dialing code
          has been removed.

     2.   All the cheezy file transfer support has been removed.

     3.   Most of the tilde escapes have been removed.  Mostly these were the
          file trasfer related ones.  See below for what remains.

     4.   Ntip ignores 90% of the remote(5) capabilities.  You can set the
          baud rate (br) and the device (dv).  Period.

     5.   All of tips variables are still present, but most don't do anything.
          It is left as an exercise to the interested user to differentiate.

     6.   By default, it operates in ``raw'' mode instead of the usual
          ``cbreak'' mode.  This means that all input processing (if any) is
          performed by the remote system.  Raw mode also disables
          ``raisechar'' and ``force'' variable interpretation.  Yes, you can
          actually run emacs on an ntip line (modulo the '~' thing).

     7.   Tip is the poster-child for fork-without-exec, creating separate
          reader and writer processes executing ``the same code.''  Ntip is a
          child of convenience and consists of a single process using
          select(2).

     8.   Ntip no longer uses uucp(1) style locking.  It relies on the TIOCEX-
          CL ioctl (see tty(4))  to provide ``reasonably mutually exclusive''
          access.  While it is still technically possible that two parties
          could open the same line and both get ``exclusive'' access to it, we
          consider this to be the source of amusing anecdotes rather than a
          bug.
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