64 pin SIMM (Mac IIFX) Specs?

[Jeff Walther]

I am looking for specifications for the 64 pin SIMMs used in the 
Macintosh IIFX and one or two of the LaserWriters (IINT, IINTX?).   I 
have the pinout from the "Guide to the Macintosh Family Hardware" but 
could use the physical dimensions, i.e. an engineering drawing.  Any 
special electronic considerations would be nice to know too.  I'm 
thinking about running off a few homebrew boards.

One of Apple's old Tech Notes states, "The IIfx has 64-pin SIMMs, 
which are different from previous Macintosh models. Developers can 
request mechanical drawings and electrical specifications of the IIfx 
RAM SIMM modules from DTS. Please send the request with a mailing 
address and include the words "IIfx SIMM information request" in the 
title of the electronic mail request or letter to facilitate 
handling."

But since that note was last updated in 1991, I'm guessing that 
wouldn't work any more.   But if one of you sent off for that 
information way back when, I would love to see it.

My main concern is that the pinout lists a separate data pin for data 
in and data out.   So even though they are eight bit SIMMs, there is 
a Data In [0:7] and Data Out [0:7] in the pin out.  It's possible, 
perhaps likely, that these are simply tied together, but it would be 
nice to see some confirmation.  The chips I've identified on IIfx 
SIMMs don't appear to be dual ported and I don't see any extra 
circuitry on the SIMM that could be making an adaptation, but I'm 
working from JPEGs so far.   If this looks feasible I'll actually 
spring for a IIfx and a few SIMMs to work from.

On the other hand, if the SIMMs require some rare dual data ported 
DRAM chips, then I'll drop the idea.

Jeff Walther