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\title{Using Terminus, the LCS Dialup Server}
\author{with excerpts from the Cisco Systems manual,\\
        {\em Terminal Server Configuration and Reference}
	\thanks{\copyright 1988-1991, Cisco Systems, Inc.}}


\newenvironment{cmd}{\hfill\par\vspace{12pt}}{\hfill\par\vspace{12pt}\noindent}


\begin{document}
\maketitle

Terminus is the LCS dialup server.  This brief document will provide a
description of some of the options and commands one may use with
Terminus, as well as some other information that the user will find
useful.  Support for Terminus includes three mailing lists:
\verb#Bug-Terminus@LCS.MIT.Edu# for bugs,
\verb#Terminus-Admin@LCS.MIT.Edu# for administrative questions, and
\verb#Terminus-Users-Request@LCS.MIT.Edu# for service info and updates
which all users, especially guests, should get.


\section{Brief Overview}

\subsection{Getting to Terminus}

The supported service uses standard data transmission at speeds from
300 to 14400 bits per second (bps).  The Bell 103 standard is used at
300bps, the Bell 212 at 1200.  CCITT standards V.22{\sl bis} and
V.32{\sl bis}\footnote{and as with all CCITT standards, the bis forms
are compatible with the older non-bis forms of the same standards} are
used for 2400, 4800, 9600, and 14400bps.

There is also capability for one non-standard---but widespread---high
speed modulation (USR-HST), this is not strictly a supported service
but is available and fully functioning.  The MNP and V.42bis error
control and compression protocols are also supported.
 
The main phone number for reaching the dialup service is {\bf
258-7111}.  This number is good for all but the V.32/V.32{\sl bis}
service; for these the number is {\bf 258-6222}.

The phone numbers for Terminus are handled by what is termed a {\em Call
Distributor}.  Calls to these numbers will automatically be routed to
free lines with the required service.  The selection of lines is done
such that successive calls will go to different lines even if the
first caller has hung up.  This should prevent a problem with a single
line from interfering with all calls.  If you have a problem; hang up
and then call right back, you will get a different line (unless there
is only one line available).


\subsection{General Command Use}

The commands described below are used to make connections, control
those connections and perform other miscellaneous operations.  Not all
the available commands are described here, but these are the ones
users will find most useful.

You may type commands in uppercase, lowercase, or any combination
thereof.  You may also abbreviate commands and other key words to the
number of characters that cause the command to be a unique
abbreviation.  For example, you can abbreviate the {\bf show} command
to {\bf sh}.

If you make a typing mistake, you can erase characters with the Delete
or Backspace keys.  Press either key to erase the last character you
typed.  To erase the entire line, type Ctrl-U.

The terminal server acts on most commands after you press the Return
key.  You can abort a local command at any time by typing Ctrl-C;
commands which open connections may require the escape sequence
described below (by default Ctrl-\verb+^ X+).

To list available commands, type a question mark ({\bf?}).  You
can often enter a question mark (help command) to obtain more
information about commands.  For example, type \verb#terminal ?# to
obtain a list of {\bf terminal} commands or \verb#show ?# to obtain a
list of {\bf show} commands.

Certain commands may produce large quantities of output.  You can
prevent the output of these commands from scrolling off the screen by
setting the height to an appropriate number (the default is 24).  At
the end of each screen, Terminus pauses and displays:
\nopagebreak[3]
\begin{verbatim}

-More-

\end{verbatim}
Type a space to continue the output; anything else will return you to
the system command prompt.

\vspace{5pt}

Here is a list of the commands that you may use.  They are described
in more detail in the sections following:
\begin{verbatim}

Terminus>?

 connect <host>       Connect to host - same as typing just a host name
 disconnect <cn>      Break the connection specified by name or number
 exit, quit           Exit from the EXEC
 name-connection      Give a connection a logical name
 resume               Make the named connection be current
 rlogin <host>        Connect to host using rlogin protocol
 show <cmd>           Information commands, type "show ?" for list
 systat               Show terminal lines and users
 telnet <host>        Connect to host using telnet protocol
 terminal             Change terminal's parameters, type "terminal ?"
 where                Show open connections
 xremote              Enter XRemote mode
 <cr>                 To resume connection

\end{verbatim}

\section{Making a Connection}

Terminus provides three different types of connections, {\bf telnet},
{\bf rlogin}, and {\bf Xremote} 

\subsection{Telnet}

{\bf Telnet} is the Internet standard terminal protocol, and the
default on Terminus.  The simplest way to use telnet is to type in the
name of the machine you want to connect to:
\begin{verbatim}

 Terminus> snark

\end{verbatim}
The above command would connect you to snark and start a session as usual. 


\subsection{Rlogin}

The {\bf rlogin} command starts a connection using the UNIX rlogin
protocol.  The full syntax of the command is:
\begin{cmd}
{\bf rlogin} {\em host} {\bf [debug]}
\end{cmd}
The optional keyword {\bf debug} enables debugging output from the
rlogin protocol.

An alternative to the Telnet protocol, {\bf rlogin} was designed to
use with the UNIX system at UC Berkeley.  For more information about
this protocol, read the manpages.


\subsection{XRemote Connections}

If your computer includes a server for XDMCP, you can use automatic
session startup to initiate an XRemote session on an NCD X terminal.

The command used to initiate XRemote using XDMCP is {\bf xremote xdm}.
This command has the following syntax:
\begin{cmd}
{\bf xremote xdm} {\em hostname}
\end{cmd}

\section{Common Commands}



\subsection{Establishing Multiple Connections}

You can have several concurrent connections open and switch back and
forth between them.  To switch between connections, first type the
escape sequence, which by default is Ctrl-\verb+^+, then \verb+X+
(press the Ctrl, SHIFT and \verb+^+ key simultaneously, let go, then
press the \verb+X+ key), to return to the sustem command prompt.

To make a new connection, use the precedure described above.  To get
back to an existing connection, use the {\bf resume} command.  Use the
{\bf where} command to list your open connections.

\subsection{Switching Between Connections}

The {\bf resume} command returns to a previous connection.  The
general command syntax is:
\begin{cmd}
{\bf resume} [{\em connection}]
\end{cmd}
The optional argument {\em connection} is the connection name or
number; the default is the most recent connection.

You can omit the command word {\bf resume} and simply type the
connection number to resume a connection.  You can also return to the
most recent session by just pressing the Return key.


\subsection{Displaying User Sessions}

There are two commands that can be used to display information about
your actve terminal sessions.  They are {\bf where} and {\bf show
sessions}.  To use, just type either command at the prompt.

The information it displays includes the host name, address, number of
characters waiting to be sent to the terminal, idle time, and
connection name.  An asterisk (*) indictes the current connection.


\subsection{Displaying Line Information}

You can use {\bf systat} to display information about the active ports
of the terminal server:
\begin{cmd}
{\bf systat [all]}
\end{cmd}
Using the optional keyword {\em all} will cause all lines to be
displayed, including those not currently active.
Here is a sample:

\begin{verbatim} 
 Terminus>systat 
 
     Line     User      Host(s)               Idle Location
    1 tty 1             AUGUST.AI.MIT.EDU        0 Dialup
    2 tty 2             CATFISH                 14 Dialup
    4 tty 4             WINGEDLION            1:13 Dialup
      
 \end{verbatim}


\subsection{Exiting a Session}

The {\bf exit} or {\bf quit} command terminates the EXEC command
parser and closes any active terminal sessions.  Enter either command
when you are finished with all sessions.  This will terminate any
connections (after confirmation) and hang up your modem.

\section{Some Advanced Commands}

This section describes in detail some more options for Telnet, as well
as a few other commands that might be of use.  The commands in this
section are not needed for most simple use of Terminus, but may be
helpful to some users.

\subsection{More Telnet Information}

The full {\bf telnet} command syntax is:
\begin{cmd}
{\bf \{ connect \verb+|+ telnet \}} {\em host} [{\em port}] [{\em /keyword}]
\end{cmd}
The argument {\em host} is a host name (the machine you want to call)
or an Internet address.  Since {\bf telnet} is the default protocol,
all that is really necessary to connect is the host name.

The optional argument {\em port} is a decimal TCP port number; the
default is the Telnet server port (decimal 23) on the host.  The
optional {\em keyword} is one of the following:


\begin{description}

\item[/route:] {\em path} -- Specifies a loose source routing.  The
argument {\em path} is a list of host names or Internet addresses that
specify network nodes, ending with the final destination.  For
example, the following command routes packets from the source to {\em
kl.sri.com}, then to 10.1.0.11, and finally to {\em mathom}:

\begin{tt}

{\sl Terminus$>$ } connect mathom /route:kl.sri.com 10.1.0.11 mathom

\end{tt}

\item[/line] -- Enables Telnet line mode.  In this mode, the terminal
server does not send any data to the host until the user presses
Return.  The user can edit the line using the standard terminal server
command editing characters (Backspace, Delete, Ctrl-U, Ctrl-W).  The
{\bf /line} keyword is a local switch; the remote server is not
notified of the mode change.

\item[/debug] -- Enables Telnet debugging mode.

\item[/stream] -- Turns on ``stream'' processing, which enables a raw
TCP stream with no Telnet control sequences.  A stream connection does
no preocessing of Telnet options, and may be appropriate for
conncetion to ports running UUCP and other non-Telnet protocols.

\end {description}


\subsection{Naming a Connection}

The {\bf name-connection} command assigns a logical name to a
connection.  You will be prompted for the connection number and name
to assign when you enter this command.  The {\bf where} command
displays a list of the assigned local connection names.

The following example demonstrates this process:

\begin{verbatim}

Terminus>where

Conn Host     Address        Byte  Idle  Conn  Name
*  1 Eng1     192.31.6.22       0     0  Eng1
   2 Term2    192.33.6.21       0     5  Term2

Terminus>name-connection
Connection number:1
Enter logical name:  my host
Connection 1 to Eng1 will be named ``my host'' [confirm]

Terminus>where

Conn Host     Address        Byte  Idle  Conn  Name
*  1 Eng1     192.31.6.22       0     0  my host
   2 Term2    192.33.6.21       0    10  Term2

\end{verbatim}


\subsection{Aborting a Connection}

You can use the command {\bf disconnect} to abort a connection:
\begin{cmd}
{\bf disconnect} [{\em connection}]
\end{cmd}
The optional argument {\em connection} is a connection name or number;
the default is the current connection.  Use {\bf where} to get a list
of your open connections.

\begin{quote}\em
{\Large	 {\bf Note:}} Do not use the {\bf disconnect} command to end a
session.  Instead, log off the host, thus allowing the host to
initiate the disconnect.  Use the {\bf disconnect} command only if you
cannot log off the host.
\end{quote}


\subsection{The Terminal Command}

The terminal command can be used to change some of the terminal
parameters.  The syntax is:
\begin{cmd}
{\bf terminal} [{\em command}]
\end{cmd}
Typing \verb#terminal ?# will show you a complete list of terminal
commands.  There are two that could come in useful:

\begin{description}

\item[escape-character] - To set the escape character for the current
terminal line, use this command.  The syntax is:
\begin{cmd}
{\bf terminal escape-character} {\em decimal-number}
\end{cmd}
{\em Decimal-number} is the ASCII decimal representation of the
desired escape character or an escape character (Ctrl-P, for example).
Typing the escape character followed by the X key returns you to the
Terminus prompt when you are connected to another computer.  The default escape
character is Ctrl-\verb+^+.

To make the Break key function as the escape character, use the 
{\bf terminal no escape-character} command.  The break need not be
followed by an ``X''.  

\item[download] - The {\bf terminal download} command is used when
running a program such as KERMIT, XMODEM or CrossTalk that downloads a
file across a terminal server line.  It sets up the terminal as a
transparent pipe that can be used to transmit data. To restore the
original parameters, type {\bf terminal no download}.

\end{description}

Two commands that you shouldn't mess with are {\bf flow} and {\bf
speed}.  They refer to the settings of the modem connected to Terminus,
and not to your terminal.




\subsection{Displaying Current Terminal Parameters}

The {\bf show terminal} command displays the configuration parameter
settings for the current terminal line.  Enter this command at the
Terminus prompt:
\begin{cmd}
{\bf show terminal}
\end{cmd}
The display includes a comprehensive report on the terminal settings
in effect, including the preferred transport protocol.

\end{document}





