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From: cmilono@netcom.COM (Carlo Milono)
Newsgroups: comp.dcom.lans
Subject: Re: DECserver multisessions through ISN
Keywords: DECserver LAT TD/SMP ISN multisessions
Message-ID: <1991Mar28.004256.16895@netcom.COM>
Date: 28 Mar 91 00:42:56 GMT
References: <1991Mar27.001042.283@bsu-ucs.uucp>
Organization: Netcom - Somewhere in the S.F. Bay Area
Lines: 47

In article <1991Mar27.001042.283@bsu-ucs.uucp> d001ucsac@bsu-ucs.uucp (Stephen P Kendall) writes:
>
>I'm connected to a university VAXcluster through a DECserver 500 (which
>says it uses LAT V5.1) through an AT&T ISN network.  The ISN network is not
>a LAN in the usual sense; it connects to the terminal or PC through the
>COM port (19.2 kBaud) rather than through special network hardware.
>
>The HELP menus on the DECserver mention an option to SET MULTISESSIONS ENABLE,
>which then allows "multiple terminal sessions, each capable of a single LAT
>service session" through the "TD/SMP protocol".  This seems to imply that
>with a "session management terminal" or a PC running suitable software, that
>multiple simultaneous connections to the DECserver's services are possible.
>
>My question:
>
>	1)  Is it possible to do this on a PC, given the hardware setup above
>	(not on a true LAN-style network, but connected to the DECserver
>	through a COM line)?

The ISN can provide multiple sessions as well, but to different ports on
perhaps different hosts/terminal-servers.  But you can think of the ISN
as a very fancy and very long RS232 cable.  To that extent, a PC or terminal
can, in essence, be 'hardwired' to the LAT Terminal Server...and it is 
actually *there* where you get multiple sessions.  I am not familiar with
the DECserver 500, per se, but if you set MULTISESSIONS, then you have
some form of key-stroke "hook" into the OS of the Terminal Server.

Here is an example:  You power on your PC, which is connected to an
Async Port of the ISN...you fire up your favorite terminal emulator
(with VT220, natch?)...you are then given an ISN prompt like 'DIAL:',
and you enter some address (like 'cluster'), and you now have a
virtual circuit connection to the T.S.

There are settings on the T.S. to enable multiple sessions - and a key
sequence to back-out of one and choose another.  You might hit BREAK-ESC
for example and be given a menu....it is quite similar to the concept
of the ISN, but it needs to be programmed.

No special software is required outside of that which your app requires,
such as VT52/100/102/220/340, etc.

-- 
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