[rescue] Interface info for IBM Dials and Buttons boxes?

[Corda Albert J DLVA]

I just finished tracing the interface out, and I believe I can say
with certainty that it's capable of RS232.  The units I came
across have a 9-pin mini-din connector on the back. I was fortunate
to get a matching adaptor cable that mates this to a rather funky
DB25 connector, which has a piggyback 9-pin molex on the back of it.
this mates to another cable (to provide power) which has a Din-6
connector (Together, both units need 5Vdc at about 1A.  Use a good
regulated power brick, since there is no on-board regulation,
and minimal filtration.) 

I traced out the wiring, and pins 2 and 3 of the DB25 go to the
appropriate I/O pins on the Max232 chip. DCD, CTS, and DSR are
tied high via 2k resistors, so they apparently don't use any
sort of hardware handshake.

One oddity.  Pin 22 of the DB25 is tied _directly_ to the five
volt supply.  My guess is that these critters support more than
one machine (via more than one adaptor cable). I suspect that
they could probably plug into a "special" mini-din port on the
back of an RS6000 which may have supplied power along with data,
or they could be used with other IBM systems via the RS232 cable
and a power brick adaptor.

There are a couple other lines available on the mini-din connnector
that are not routed through the adaptor cable, so whatever system
drove this directly may have been able to do some other sort of
hardware tricks via the interface.  At this point, all I'm concerned
about is trying to get this unit working via RS232.

If you decide to start experimenting with these critters, and
you need the pinouts, let me know... BTW, make certain if you
use their RS232 adaptor cable, that you DISABLE the connection
to pin 22 (Ring Indicator) so you don't feed 5Vdc back into
your serial port UART (probably not a _good_ thing).

Again, any info would be appreciated on the command set for this
critter. I'll know if it responds to "h", "?" or any other typable
character :-) in a day or so, soon as I rig up a power supply.


-al-
-acorda at 1bigred.com





> -----Original Message-----
> From: Julius Sridhar [mailto:vance at ikickass.org]
> Sent: Thursday, February 21, 2002 2:37 PM
> To: Eric Webb
> Cc: rescue at sunhelp.org
> Subject: Re: [rescue] Interface info for IBM Dials and Buttons boxes?
> 
> 
> On Thu, 21 Feb 2002, Eric Webb wrote:
> 
> > > > and 6094-010). Physically, they look very similar to 
> the dials and
> > > > buttons boxes used on SGIs.
> > > >
> > > > So far, I've been able to determine that these are 
> RS232 interfaced
> > > > critters.
> > >
> > > Try sending it an `h'--not as daft as it seems;  one of 
> the various SGI
> > > gadgets replies with a help screen on how to communicate with it.
> > > (Spaceball?).
> > >
> >
> > If no one gets anywhere with this let me know.  I think I 
> can get my hands on
> > one of these at work and can try to help hack it.  For some 
> reason I remember
> > a manual as well, but I'm not sure.  We dug it out of the 
> scrap pile a couple
> > months ago, scratched our heads and then said "Oh!"  Got a 
> ton of those
> > digitizer pads that they work with, but I don't believe 
> those are RS-232....
> > Sridhar?
> 
> You know what, I've never bothered to find out whether these 
> devices were
> RS-232 because there's a "Tablet" port on the back of RS/6K's 
> that these
> guys plug into.
> 
> Peace...  Sridhar
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