DW780 Unibus Adapter

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The DW780 Unibus Adapter was a UNIBUS bus translator for the VAX-11/780's Synchronous Backplane Interconnect.

It was implemented on four hex cards:

  • M8270 - UBA SBI Interface (USI)
  • M8271 - UBA Control Board (UCB)
  • M8272 - UBA Map and Data Path (UMD)
  • M8273 - UNIBUS Address and Interrupt (UAI)

They mount in a custom 6-slot backplane (normally mounted next to the main CPU backplane). 2 slots (on the back of the backplane) are used to hold double-width i) M9044 UNIBUS terminator, and ii) an M9042 paddle card, which carries the UNIBUS out on three flat cables (DEC part number 70-133622-00), normally to an 'expansion I/O connector' on the side of the cabinet, and thence to a BA11-K mounting box mounted in an expansion cabinet. (There are some 'UNIBUS VAX' configurations where there is a DD11-C or DD11-D backplane in the main cabinet; in these, the flat cables run directly to an M9014 paddle card in the DD11. See pp. 15-16 and 65 of MP00539 for coverage of this configuration; see also chapter 12 of the 'VAX-11/780 Installation Manual'.)

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