This phone utility provides a procedure for calling another user, and
a procedure for answering a user who is calling you.

When a connection is established, the tools create a window split in the
middle which displays the characters typed by each user. Both users' keyboards
will not respond to Environment commands while they are interacting with the
phone utility. Either user may terminate connection at any time by entering
a CONTROL-C.

The Call procedure has three parameters:

   User    -  name of the user to call.

   Session -  specifies a particular session.
              The default specifies any session
              
   Wait    -  The number of seconds to wait for an answer
   
   This procedure will send a message to the called user that a caller is
   waiting.  The calling user gets a ringing message in their window.

   
The Answer procedure has two paramters:

   User    -  The name of the calling user to answer.
              The default indicates the first caller the program finds.
              Most often there is only one caller, but there might be more.
              
   Session -  Specifies a particular session.
              The default specifies any session.