On 2014-06-13, Michael A. Terrell wrote:
"DoN. Nichols" wrote:
On 2014-05-19, Michael A. Terrell wrote:
"DoN. Nichols" wrote:
[ ... ]
I have a half dozen pieces of test equipment with the IEEE-488
interface. There are web pages with USB to IEEE-488 interfaces you can
build.
Hmm ... Can they be talked to with something other than Windows?
I've got an HP card in a machine running Ubuntu linux with an open
source driver for that which happily talks to my HP digital 'scope and
my HP DMM.
Yes. In fact, they were originally controlled by HP's lab style
computers. All you need is a computer with a working HPIB/GPIB/IEEE-488
interface card and the commands for that instrument. The user manual
usually lists the commands for each instrument.
I meant could the USB to IEEE-488 interfaces be talked to with
something other than Windows systems. I actually have a PCI IEEE-488
board in one linux box, but I would like to also have some IEEE-488
communications from my Sun Blade 2000 systems.
I've got one of the HP 9826 (Series 9000-226) machines from a
hamfest -- but much to my dismay, apparently one of the pair of ROMs
which make the system's initial boot software (this one doesn't have a
language in ROM as some of them did) is corrupted. I see on the screen
various status messages and prompts, with every other character
unintelligible -- because the ROM that it is in is damaged -- so I can't
do anything with that machine. A pity, the price was nice, and it came
with the BASIC floppy set, and a couple of IEEE-488 cables.
I've also got a couple of Tektronix 6130 systems (National
Semiconductor 32016 CPU) which have the IEEE-488 interface too, but the
system is ancient, and the programs necessary to format a SCSI disc on
it are missing. The only disc is an 80 MB MFM disc -- sort of made of
unobtanium these days. :-)
Also back it the days of the HP 9825 (a simpler machine with a
weird language called "HPL") I constructed an interface to allow the
9825 to control a Fluke HV power supply which could be commanded to
produce a voltage (up to 2048 Volts, IIRC) in pure binary. I used a
6800 CPU and a 68488 HP-IB/GPIB/IEEE-488 controller chip.
The interesting thing about the DB-25 and the RS-232 serial port
is that the standards were very careful about the voltages which the
pins would accept and output, and lots of other things, but it did not
bother to specify the actual connector to use. It *could* have been any
of a number of other connectors, as long as it had enough pins. I think
that the use of the DB-25 for that was started by Ma Bell in their
modems -- and everyone else followed suit. :-)
It was a good choice. A reliable connector from Canon, not something
custom from an unknown source.
Agreed.
Indeed. But interesting that the *standards* did not specify a
connector at all. :-)
Yes, but most companies picked a common connector so they could talk
to other equipment without stocking hundreds of different cables. A few
oddballs used very expensive and hard to find connectors. Some used
another cheaper connector to save a few cents, like the Heathkit H-14
printer that used a straight line molded nylon connector like those used
on switching power supplies.
That might be from their association with DEC. I bought a DEC
LA-36 dot matrix printer which had as its serial interface a flat
plastic connector with a tab which set the keying which was by default a
TTY current loop interface, and had to get an add-on board to make it
RS-232. :-)
It was a nice printer for a while -- until a really hot day
caused the double-sided tape which held the carriage position encoder
wheel in place to soften and let the encoder go off-center. At that
point, it would crash loudly into one of the stops. :-)
Enjoy,
DoN.
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