Info-3b2 Digest, Number 25

[Info-3b2 Mailing List]

                           Info-3b2 Digest, Number 25
 
                           Monday, October 17th 1988
 
Today's Topics:
 
                                      X.25 
                              Re: various 3B2 stuff
                              RJ45/RS232 Connectors
----------------------------------------------------------------------
 
Subject: X.25 
Date: 15 Oct 88 21:46:23 EDT (Sat)
From: grs at alobar.ATT.COM (Gregg Siegfried)

Hi, fellow 3B2 enthusiasts..

If anyone has connected their 3B2 to an X.25 network, such as Accunet(tm), 
telenet, tymnet, etc., I am interested in hearing about it.

Also, if you speak X.25 to another machine via a point to point connection
that would be cool as well.

What I would like is the card you use, software, speed of your link, whether
you use SVCs or PVCs or both, and all that kind of stuff.

Feel free to email this info to me, or reply directly to the list.

Thanks,
Gregg Siegfried
grs at alobar.att.com
{well connected site}!att!alobar!grs

------------------------------
 
Subject: Re: various 3B2 stuff
From: pacbell!att!ocrjd!randy

Addressing Steve Friedl's comments:

:                                            ......It appears
:     that there are multiple ways of cabling the drives in a
:     /400, and in their units the cables route up from the
:     bottom, so the upper drive is at the end of the cable --
:     ours don't work this way.

  It *should* be.....  But then, maybe we were building them differently
at one time (that's not my area).

:     To sum up, the terminator goes in the drive at the physical
:     end of the daisy-chained control cable (the wide one)
:     regardless of drive-select numbering.

  Exactly.  I would have hoped that they specified it in this way.  Too bad
that they specified it based on drive select numbers.  *Always* terminate
a transmission bus at the end (though you can usually do it at other places
on short runs and never have any problem).

:*    I've installed a 72MB drive in an XM unit in a 3B2/310.  I
:     installed the resistor pack in the new drive, and I was in a
:     quandry about the little SIP resistor pack inside the 310.
:     I removed it but now am pretty sure that was not The Right
:     Thing.  Does anybody know how the terminator in drive zero
:     gets disabled when a second drive is installed?

  No, you *did* do The Right Thing.  There are two sockets on the 310 ADI board
(that's what the little tiny board at the back of the 310 that holds the two
cable sockets is - it stands for Auxiliary Disk Interface - big name for such
a tiny board :-).  One is connected to the bus, the other is merely a socket, as
I recall, on which to store the unused SIP (now, don't ask me which is which,
but it is easy to determine, as the ADI is a simple double sided board).  When
connecting up the external cables, you are supposed to move the termination to
the end of the bus, which in this case means removing the resistor SIP and
installing the resistor DIP at the end of the bus (or leaving it, as it
probably is already installed on the XM).
  Following the above simple convention: With no XM attached, there should not
be any termination on the internal drive on the model 310 and there should be
a terminator SIP on the active ADI termination sockets as it is built at the
factory.  If there is a termination DIP on the internal drive, there should
not be a SIP in the active ADI socket.  Add an external drive, and all internal
terminators should be removed.  Interestingly, I have found that the CDC
drives are not very picky about termination.  I have seen some run fine with
no, or even double termination (both big no-nos).

Can't help with the rest of the questions....

Randy Davis					UUCP: ...(att!)ocrjd!randy
						      ...(att!)occrsh!rjd

------------------------------
 
Date: Sat, 15 Oct 88 9:29:49 EDT
From: lll-tis!ames!mailrus!umix!marae!jwh (James W. Howe)
Subject: RJ45/RS232 Connectors

Can someone recommend a good place to get RJ-45 to RS-232 convertors at
a reasonable price?  I need the type that don't come prewired.  I need
to create a custom connection to connect a 3b2 serial port to a Computone
serial port residing on a Compaq 386.  

Jim

..!umix!marae!jwh             

 
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