The vendor who sold me the MicroVAX CTI card found the memory daughter card. It 's missing a few memory chips, but otherwise looks in good shape. Can;t wait to get it, add the missing chips and do some testing. Still a long shot to make it do anything, but it's bound to help.

  Took some pictures of the MicroVAX CTI card, and another odd card I got - an 8086 CTI smartcard. See 'em both at https://rsx11.blogspot.com/2022/09/microvax-and-8086-smartcards-for-dec.html -- Lee K. Gleason N5ZMR Control-G Consultants lee.gleason(a)comcast.net

On 9/9/2022 5:39 PM, Warner Losh via cctalk wrote: I have one of the Virtual Microsystems PC-Bridge CTI boards (the commercial 8086 board). One of the more interesting things about it is that it has its own video circuitry.  It's built up around an Hitachi HD46505/HD6845 CRT controller with 16 KiByte of video RAM and a character generator ROM (a lot like a CGA).  The board has one of the "long" ZIF connectors with the additional 30 pins which carry, among other things, the analog video signals wired directly to the monitor port.  The board superimposes its own video onto that of the system.  The PC-Bridge host software just clears the screen and turns off the cursor.  In some cases the host software can pop up host video simultaneously with the PC-Bridge video. I assume the PC-Bridge hardware looks for sync on the "GREEN VIDEO" signal or, possibly, the driver software uses the host video sync interrupts to do a kind of software PLL to lock the video sources together.  Somehow the fact that both the system and the PC-Bridge board simultaneously drive the analog video lines works out. Hairy stuff. Another really interesting thing about the PC-Bridge board is that it has DEC-labelled parts on it.  I'm not talking about things like "proprietary" bus interfaces chips.  The DRAM SIMMs (used for the board's main memory) have the digital logo and a DEC part number on them (1418744-00). In addition the chips are labelled with the DEC convention (Exx) and are numbered E1, E2,... starting in the lower right hand corner, with the first chip of each column being labelled on the board, just as on DEC boards. This made me suspect that the PC-Bridge board was actually designed by DEC, or maybe the design was originated by DEC, and so maybe the board Lee got on eBay was an earlier version of the PC-Bridge. But it's clear that isn't the case -- Lee's board has a 60-pin ZIF connector and no apparent CRT controller chip. I was never able to get the original Virtual Microsystems software package for my board, but from a friend I did find a Pro hard drive image with the PC-Bridge application software installed on it.  With that I was able to regenerate the installation diskettes. All of this is an incredibly roundabout way of saying: I was going to offer my reconstituted PC-Bridge installation diskettes, but I really doubt they'll work.  In fact, I really doubt the software to drive Lee's board is easily obtainable at all, given that his board bears no real resemblance to the PC-Bridge board which, AFAIK, was the only 8086 CTI board commercially available. From what I see in the photograph I'd guess that the board works much more like the DEC "CP/M" (Z80) board.  In that case there's a simple mailbox register with interrupts wired up on both sides. When using the CP/M board the host is mostly just a dumb serial terminal with some side-channel floppy and file access.  That's why there's no graphics at all with the CP/M board. --Bjoren