1 HOST
HOST allows a VAX terminal to be used to communicate with other
computers  over an outgoing port selector or modem line. HOST will
allow you  to connect to a remote computer through the VAX  and will
transfer files at 300, 1200, 2400, 4800 or 9600  baud. No form of
error detection or correction during file transfer is supported. 

You may run host by simply typing HOST if you put into your LOGIN.COM file

     $ @LIB:[LIB.HOST]SETUP

You may also run the HOST procedure directly typing 

     $ @LIB:[LIB.HOST]HOST
2 COMMANDS
HOST normally sends all terminal input directly to the remote system.
However,  if  you  input a NUL (ASCII code 0) (CONTROL space-bar on a
VT-100, CONTROL @ on an ADM3 terminal), the NUL character is not sent
to  the  remote system.  Instead, HOST prompts you for one command to
HOST itself.  The legal commands are:

       CHANGE  ;change remote system, baud rate, parity, or
               ;duplex(full/half) or other parameters.
       EXIT    ;exit from HOST, returning you to the VAX,
               ;and freeing the line to the port selector
       HELP    ;access this HELP file
       RECEIVE ;transfer ASCII file from remote system to VAX.
       SEND    ;transfer ASCII file from VAX to remote system.
       TURN    ;turns session logging on or off
       VAX     ;exit from HOST, returning you to the VAX,
               ;but leave the connection to the remote system
2 CONNECT
When HOST is run, it will ask you several self-explanatory questions,
to  set  up suitable parameters.  After answering them, your terminal
will appear as though it is connected to the port-selector.   Type  a
carriage   return   to   get   the   port-selector's  attention  (the
FERMILAB=; message) and answer with the  class  code  of the computer
you wish to communicate with. You will now be connected to the remote

When you have established the connection to your  remote  system  all
subsequent  terminal input, with only one exception, is sent directly
to the remote system.  Login on the remote system  and  do  what  you
like.   The exception is when a NUL (ASCII code 0) character is typed
(this is a control-space-bar on a VT-52 or VT-100 or ADM-3 and also a
control-@  on  an ADM-3 terminal ).  This character is intercepted by
HOST and allows you to enter commands to HOST to  transfer  files  or
perform various other functions.

The  NUL  'break' character may be changed to some other character by
defining the  logical name  HOST_BREAK_CHAR  as a 3 letter string for
the octal value of the character required.

Type HELP HOST COMMANDS for a list of the HOST commands.
2 ERRORS
Occasionally you may find that instead of the  port  selector  prompt
you have a connection to a remote computer already established.  (The
automatic disconnect of the previous  HOST  user  has  failed).   You
should  exit  from  the HOST program and try again.

If you get the message

          ERROR ON ALLOC MODEM

then someone else  is  using the  HOST  program and the line you have
selected as HOST's output port.
2 EXIT
This command causes the HOST program to exit, returning  you  to  VAX
command  level.  This command does not log you off the remote system.
The connection to the port-selector will be broken.
You should log off the remote system before EXITing HOST.
2 FILETYPE
ASCII  source  files may be transferred with HOST.  Files should have
the attribute  'CARRIAGE RETURN'.   Files  with  attributes  'FORTRAN
CARRIAGE RETURN' or 'NONE' will not transfer correctly.
2 RECEIVE
This command allows a file  transfer  to  the  VAX  from  the  remote
system.  You must be logged in on the remote system.

For all supported systems you will be prompted for a  destination  file
name  on  the local VAX and the source file name on the remote machine.
The file may optionally be typed out at the terminal  as  it  is  being
transferred.   Typing any character on the terminal during the transfer
will terminate the transfer immediately.   When  no  more  records  are
being  received you should then press the RETURN key, or any other key,
and this will terminate the transfer and close the received file.

To receive a file from unsupported systems  you  should  use  the  TURN
option described below.
2 SEND
This command will transfer a file from the VAX to  a  remote  system.
You must be logged in on the remote system.

For supported systems you will be prompted for the source file name  on
the  local  VAX  and  the  destination  file name on the remote system.
Optionally, the file may be typed out on the terminal as  it  is  being
transferred.   The file transfer will terminate automatically at end of
the file.

The HOST program sends a carriage return at the  end  of  each  record.
The  next  record  is  sent when the remote system has responded with a
handshake character, normally a line feed.  If this synchronization  is
not  appropriate for the remote system, you may use the DELAY or CHANGE
commands to slow transmission.  (See section on HOST COMMANDS) Type any
character to terminate the transfer.

For unsupported systems you will be prompted for the source  file  name
on  the  local VAX.  You must have previously typed the commands to the
remote system to cause it to receive terminal input into a file.   This
command  would  be  CREATE  on a VMS system, or TEXT on a Cyber system.
After  the  file  is  transmitted,  you  must  issue  the   appropriate
termination commands to the remote system.
2 SESSION
When  Session logging is turned on, you will be asked for the name of
a disc file on the HOST VAX, which will be used to record your entire
session  on  the remote computer.   Both  commands you type in to the
remote computer (for Full Duplex connections)  and responses from the
remote system will be recorded.
2 SYSTEM
Five types of remote system are supported.  By  this  is  meant  that
suitable values for the line DUPLEX and PARITY are provided, and when
file transfer to or from the remote  system  is  requested,  all  the
commands necessary to set up suitable terminal characteristics on the
remote system and make the file transfer, are issued automatically.

The remote system type should be entered as a character string.   The
supported types of system are:

            CYBER           Fermilab NOS 2 Cybers
            PDP/RSX         PDP-11 running RSX-11M
            RT/PDP          PDP-11 running RT-11
            UNKNOWN         Generic system
            VAX/VMS         VMS 4
2 VAX
This command causes the HOST program to exit, returning you to VAX
command level.  In this case, the port-selector connection to the remote
system is not broken. You may resume your remote session later by just
reissuing the HOST command. 

When you exit from HOST with the VAX command, only information relating
to the line and system connected to are preserved.  Any other internal
parameters you have set up or session logging options you have set, will
return to their default values.  They must be reset when HOST is run
again. 

You should use this command only for relatively short periods, in order
to keep the modem lines free for other users.
2 WRITEUP
More detailed documentation of the HOST program is available as
library writeup PU0065.
