Mystery UNIBUS Boards?

Greetings All, Can you help identify these UNIBUS boards? They were found in a BA11-K expansion box in a VAX 11/750. The VAX was used to run the equipment in an MRI trailer. I didn't remove the system and don't know to what type of equipment it was originally connected. 1) Full size genuine DEC hex board, no "M" number on spine. "DIGITAL" and "BSWU-T" etched on front. Two stickers, marked "835084" and "4522 117 2760". 93 TTL chips, 18 PAL chips, 5 DIP switch blocks, two 50-pin connectors for ribbon cables. On rear side, "4522 111 91963" etched and a sticker with "PR32.4B" and "MB6024ET". 2) Plessey Peripheral Systems quad board. Marked with "P/N 703680- 100E" on front, "703679-001 REVB" on rear. 7 chips with stickers "218 101C, 102C, 103C, 104C, 105C, 100 UK30, UK2A". 62 TTL chips. 1 50-pin connector with cable to what appears to be an interface board (#3 below). 3) 8" by 10" board connected to Plessey board above. 2 50-pin connec- tors on top. Etched with "C-FTR", "FDD-FTR", "FTR-FTR". 12 26LS31 & 32 chips, 10 TTL. Instead of card-edge fingers, has 2 3-level male 3x32 pin AMP3485 connectors which plug into corresponding female receptacles in BA11-K box (one group of hex slots replaced with these). Any help identifying these boards is appreciated. Doubt I'll ever use them, but nice to know what they might be! BTW - Posted this inquiry to comp.sys.dec & alt.sys.pdp11 awhile back so it may look familiar. Thanks, Jason Brady jrbrady(a)mindspring.com Lynnwood, WA