IBM synchronous interface problems

[Kevin Darcy]

In article <488 at mtndew.Tustin.CA.US> friedl at mtndew.Tustin.CA.US (Steve Friedl) writes:
>Hi folks,
>
>     I am wallowing once again on this IBM 3270 interface.  My
>customer has a 3B2 and wants to talk to the VisaNet Automated
>Clearing House, and the PC we have to interface with has a 3270
>coax card in it (IRMA, I think).  It is my understanding that
>this coax expects to talk to a host computer.

More or less. From what I know of IRMA, it makes the PC look like a 3278/79 
IBM tube which wants to connect to a 3174 or 3274 cluster controller via coax.
The controller's role in this connection being (as always) to pass data back 
and forth between tube(s) and the host.

>     On the 3B2 side, we can get the ISC (Intelligent Serial
>Controller) card with many various software options, but I
>believe that ultimately the 3B2 looks like a 3278 (?) cluster
>controller.  The ASCII terminals on the 3B2 will appear as 3270
>terminals, and the synchronous side of things also expects to
>talk to a host.  The sync interface is with a DB25 running what I
>believe is RS-232.

Ultimately the 3B2 can look like a variety of things with the various pkgs 
from AT&T, but I think the one that you are referring to is the "SNA/3270" 
package. That allows the 3B2 to look like a 3274 controller. But, as you 
describe, ONLY TO THE HOST. The "tube" side is implemented purely in 
software, using a separate 3278/79 emulator that runs on the 3B2, communicates
with the SNA "controller emulator" via IPC, and makes the 3B2's async 
terminals look like synchronous IBM tubes to the host. 

To the best of my knowledge, there is no way to use the IRMA board to any
kind of advantage in this setup. Both pieces of hardware connect only to 
"higher level" nodes in the IBM SNA hierarchy. They don't connect with each 
other in any obvious way.

If you had a LAN running, maybe that would give you another connectivity path 
to the 3B2 that you could use as an alternative to IRMA. (I just had a word
with our LAN admin, and he thinks that some products from AT&T could maybe
make that possible in the near future).

Otherwise, the only way I see you achieving good 

			3278 -> 3174/3274 -> (host)

connectivity is by scrapping the idea of using the 3B2 in the setup. BUY the 
3174 or 3274 node - it may be comparable in price to do that rather than
buy ALL of the AT&T hardware and software anyway. Either that, or maybe some 
wizard in comp.protocols.ibm(?) has some way (RJE?) whereby a coax tube can 
connect to a modem via some box, and on up to VisaNet. Expect to buy some 
more serious hardware than just an ISC card, though.

Actually, AT&T used to make the 6544 - a 3274-compatible - but I heard that
they sold that business to Telex...

>     Is this understanding correct?  My customer has hardware
>sitting idle until I can figure this out, and I am having the
>growing feeling that I am S.O.L.

We live and breathe AT&T host connectivity products here at CFC, and we've
managed to get our 3B2's to talk reasonably well to our host. Some of the
newer versions promise the ability to talk true peer-to-peer as well. But it 
definitely makes no pretences of being able to talk "downwards" to lower-level
SNA nodes. I had a request for a side-application similar to what you 
describe, and after racking my brain for a solution, I too came to the 
conclusion that we were SOL.

And since the demand for this kind of thing is relatively small, don't expect
AT&T to be rushing along with solutions, either.

------------------------------------------------------------------------------
kevin at cfctech.cfc.com 		  | Kevin Darcy, Unix Systems Administrator
...sharkey!cfctech!kevin          | Technical Services (CFC)
Voice: (313) 948-4863 		  | Chrysler Corporation
Fax:   (313) 948-4975 		  | 27777 Franklin, Southfield, MI 48034
------------------------------------------------------------------------------