Interesting. I think these came from that E-COM US Postal Service thing in the late 1980's where the USPS built a pilot system to allow you to go into a post office, give them a letter, then they would scan the letter, route it through a network of pdp11's to the destination PO where it was then printed out and delivered. Yes, I think this was when a Fax machine was a very very big thing.

Interesting part is they used these boards for interconnections. The actual node was a pdp11/23 CPU with 256kb of memory, one or more of these things (which if I recall could handle 8 serial lines each), a multifunction board with clock, parallel interface (for printer), serial ports, and of course a pair of RM02 disk drives.

Before you consider that to be an impossible system, each system had a special Plessy bus in a BA11 type chassis that had a voltage regulator to make the +12, a Q bus/Unibus backplane that had a Plessy Quineverter to talk to the Unibus stuff. Even the RM02 so the Quniverter did have DMA capability but I don't recall if it has a unibus map (I have one or two of those here somewhere as well. I have a lot of stuff)

This is how Doug and I met at Alan Frisbee's place in Greenbelt to split a horde of RM02 disk drives and other stuff. Man this is going back years, but I think I still have a lot of the documentation for this project somewhere in the paper piles, it was a weird concept.



On 10/7/2020 12:36 PM, Al Kossow via cctalk wrote:
On 10/7/20 8:29 AM, Chris Zach via cctalk wrote:
That sounds like it, and I might have been the one to upload the drivers. Let me find one in the shed and take a picture.


https://pubs.usgs.gov/of/1988/0185/report.pdf

https://pubs.usgs.gov/of/1991/0262/report.pdf

from Larry Baker


they were popular X.25 cards that had BSD support
I think that's what we used at Apple to get on NSFnet

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