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From: nagy%warner.hepnet@LBL.ARPA.UUCP
Newsgroups: comp.os.vms
Subject: RE: DECServer-200 Intercommunication
Message-ID: <870912093131.026@Lbl.Arpa>
Date: Sat, 12-Sep-87 12:31:30 EDT
Article-I.D.: Lbl.870912093131.026
Posted: Sat Sep 12 12:31:30 1987
Date-Received: Sun, 13-Sep-87 08:37:50 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: world
Organization: The ARPA Internet
Lines: 48

>We wish to confirm some technical information about DECServer 200s,
>also known as DSRVB-AB, namely:
     
>1. On a single DECServer 200, can two terminals communicate with each
>other, e.g. in practice can a PC use a printer?
     
Two terminals can "communicate" with the BROADCAST command.  This allows
one user to send a short message to another user.  See 2nd answer for more.

>2. On two DECServer 200s connected to the same ethernet, using LAT-11, can
>a terminal on one of the DECS200s communicate with a terminal on the other?
>If this is the case, how would the "source" terminal (say a PC) address the
>"destination" terminal (say a printer) on the other DECS200, that is, what
>command would be used?.
     
No, a terminal cannot communicate in any way to a terminal on another DS200
except for...

Besides ports on DS200's being able to "originate" connections, ports can
be declared to be services which can "receive" incoming connections.  This
can be used for:

	- "Reverse LAT" to connect to a host computer which does not support
	  the LAT protocols on Ethernet but which has async terminal lines
	  which can be connected to a DS200.

	- Outgoing modem connections.

	- Printers.

We have experience with the later: we have 2 Printronix-300 printers
connected to two different DS200s.  We drive the printers with print
queues on several VAXes; we have not tried to drive them with PCs.
In all of the above cases, these items are declared as "services" by
the DS200 which hosts the ports.  These services then appear as such
to any other DSxxx or VAX on the network which can access LAT services.
If I do a SHOW SERVICES from "Local>" on my LAT line, I see not only
our VAX host services but also WH12W_PRINTRONIX service for the printer
on our floor.  As far as PCs talking to these services, I know that
DECnet/DOS supports LAT connections with its SETHOST program but I
don't know if DECnet/DOS or anyone else supports PC connections to
LAT-served printers.

= Frank J. Nagy   "VAX Guru"
= Fermilab Research Division EED/Controls
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