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From: wa371@sdcc12.UUCP (wa371)
Newsgroups: net.unix-wizards
Subject: how to interface IBM bisync to UNIX rs232, a summary.
Message-ID: <320@sdcc12.UUCP>
Date: Wed, 22-May-85 02:29:46 EDT
Article-I.D.: sdcc12.320
Posted: Wed May 22 02:29:46 1985
Date-Received: Sat, 25-May-85 07:41:39 EDT
Organization: U.C. San Diego, Academic Computer Center
Lines: 65
Keywords: IBM bisync, twinax, UNIX, RS-232

Question posed to the net:  How can I interface IBM bisync with 
			    UNIX having RS-232 ports?
Replies:
::::::::::::::::::
From: Cliff Bamford <sdcrdcf!randvax!bamford@sdcsvax.sdcc12>

Your question needs more careful formulation. The following may help.

EIA RS232C and several roughly equivalent standards (RS422, CCITT V.29,
X.21bis, etc) specify electrical properties, pin assignments, and
pin-level signalling sequences between either:

	a modem and a terminal (rare in traditional IBM environments)
     or a modem and a cluster controller (much more common - eg, 3274s)
     or a modem and a front end (the host side of a link -- usually a 37x5)

SDLC is a standard that specifies message formats and message exchange
sequences. The messages flow in and out OVER the RS232 connection, but
RS232 doesn't care what the messages contain -- only the SDLC partner
at the other end of the link cares -- and his only interest is to
insure checksums match, acknowledgements arrive, etc.

Above both of these is SNA, which is a standard that defines the CONTENTS
of the messages, and message content exchange sequences.

Most non-World-Trade IBM SNA/SDLC systems already employ RS232C (although
they use a strange version of a bus/tag connector instead of DB25 at the
37x5 side).

Now, what's your question?

Cliff Bamford, Data communications consultant
(408) 662 0176
ARPA:     bamford@Rand-Unix
UUCP:     {decvax, sdcrdcf, vortex}! randvax!bamford

::::::::::::::::::::::
From: dcdwest!ittvax!decvax!genrad!mit-eddie!cybvax0!fbp@sdcsvax.sdcc12 (Rick Peralta)

In article <279@sdcc12.UUCP> you write:
>Does anyone know how to interface IBM 5251 terminal protocol, "SDLC"
>synchronous, with RS232?

Look at a Black Box catalog for a protocol converter.  It is the easiest.
The cost is about $2-4K.

Rick
...!cybvax0!fbp

:::::::::::::::::::::
end of replies.

PS:  Black Box does indeed offer as protocol converter that seems to
fit.  It is their model PQ-4(B).  It has twinax inputs and an RS-232
output.  It supposed to work with system 34, 36, 38 computers and
emulate 5251 terminals.  It is available as either bi-directional
or receive-only.  Either version is listed in their catalog for $1645.-
I have not tried it,  and the person who answered their technical support
line, (412)746-5565, apparently had never heard of UNIX.
Caveat emptor.

Bernd <bear-nd> 
(Not affiliated with, nor speaking for U.C. San Diego)
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