I'm assuming the flavor mac you have does not have a PCI bus inside.  Those 
can use the PC cards with the mac driver.

What about the National Instruments ethernet to GPIB card, complete with 
Max OS X drivers
http://www.ni.com/mac/mac_gpib.htm
http://sine.ni.com/apps/we/nioc.vp?pc=res&cid=10622&lang=US&p_0=manual

Then this company has a USB to GPIB controller module
http://www.icselect.com/gpib_ds.html

Finally, if you go to
http://www.measurementcomputing.com/

And search their GPIB products, they have controllers and chips that you 
can buy to roll your own.
They have  40 pin DIP and 44 pin TQFP controller chips that sell for $10 in 
single piece quantities.

Scott


At 01:13 PM 3/28/05, you wrote:
>Good day,
>
>I'll do the short version first, then the detailed one after:
>
>I need a GPIB to RS232 or USB interface.  I've only seen multi-hundred
>dollar boxes on the web, and have to believe that someone has cooked up
>a piece of AVR (ideally, or PIC) code that eats GPIB and spits out one
>of these formats.  Maybe there's a Windows driver that fools the OS into
>thinking a com-port is GPIB, or maybe a terminal-like thing that lets me
>type raw GPIB commands...
>
>
>
>Detailed explanation (or, what I'm _really_ trying to do):
>
>I have this old piece of Tektronix gear that plugs into their analog
>7000-series scope mainframes, called a 7D20.  It is a 3-slot wide plugin
>that is basically a digital scope that uses the mainframe for power and
>display.  It is two channel, each 70MS/sec, which is plenty fast for
>much of what I need.  And it also has this GPIB port on the front...
>
>The tricky bit is that I have no PCs to plug a cheap ISA or PCI GPIB
>card ("eBay specials") into; I use a Mac laptop at my bench, and run
>VirtualPC when I need to, with an RS232 -> USB converter.  It would be
>exceedingly inconvenient, verging on impossible, to have an entire PC
>dedicated to GPIB.  If anyone can point me towards something that can
>assist in getting data from the scope to the computer (if you're about
>to say "digital camera", I'm there right now!), I'd love to hear about
>it.
>
>Thanks!
>
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