Any difference between VAX Q-bus and PDP-11 Q-bus cards?

On 12/06/2017 09:55 PM, Jon Elson via cctech wrote: Aaron, Save the plate though as they are scarce... MicroVAX used Q22.? The thing to be wary of is the Q-bus spec allows for slots ABCD (wide) and also ABAB if its ABAB its easy and no big issues unless....? They can also be ABABAB (hex wide QBUS CORE). Whats that mean... AB is the address, data and control bussed connectors and CD are usually parallel bussed but may have odd voltages or order to the signals for some of the wide cards that (usually RL and Memory) need them.? Its not unusual for a bus to be mixed? like BA123 (uVAXII) where the first 3 or 4 slots are ABCD and the remaining are ABAB. IF the board requires ABCD such as the two board set RLV11 its important as the two board talk between them selves on the CD portion of the bus. Also many of the uVAX and some later PDP-11 (J11based) the CD bus was wired differently for memory. In most cases the ABCD portion of the uVAX backplanes are only a few slots and then it reverts to ABAB. FYI if your in the ABAB area make sure you keep the bus grants and interrupt grants continuous. I know of this as I have PDP-11 and uVAX systems from LSI-11 though uVAXII/GPX.? They are all Q but there are more differences than Q16/Q18/Q22 due to the mechanical variations. Qbus board can be used in any system if they match the bus width (Q22 usually for uVAX) and you pay attention to where you put them.? This includes a lot of the PDP-11 Qbus cards.? Allison