RH780 Massbus Adapter
From Computer History Wiki
The RH780 Massbus Adapter was a MASSBUS device controller for the VAX-11/780's Synchronous Backplane Interconnect.
It was implemented on four hex cards, which mount in a custom 6-slot backplane:
| Slot | Board | Acronym | Function |
|---|---|---|---|
| 1 | M8275 | MSI | SBI/MBA interface |
| 2 | M8276 | MIR | internal registers |
| 3 | M8277 | MDP | MASSBUS data paths |
| 4 | M8278 | MCP | MASSBUS control paths |
One slot (5) is unused, and one slot (6) is used (on the back of the backplane) to hold a hex M9041 paddle card, which carries the MASSBUS out on three BC06R flat cables to what appears to be a standard MASSBUS connector, in an 'expansion I/O connector' on the side of the cabinet.
See also
External links
- RH780 Massbus Adapter Technical Description (EK-RH780-TD-001)
- RH780 Field Maintenance Print Set (MP-00499)
- VAX-11/780 Installation Manual (EK-SI780-IN-002) - contains a section on the RH780, Chapter 7 (on pp. 63-66 of the PDF)
