plotters again

[Brent Hilpert]

Tony Duell wrote:

> You _will_ lose the digitising functionality if you use the HPIB
> connector and set the machien to 'listen only' (if you can do that, most
> HP HPIB plotters do have that feature). In that mode there is no way the
> plotter can output data.

Of no relevance to me.

> If the 9872 is like that, it should be very easily possible to work out
> what the 9815 interface is doing, since presumanbly it's also mostly

I had no qualms or questions about what it is doing, it appears quite
straightforward.

> handled in hardware, possbily even much the same hardware. From what
> you've said, it must be more than just a listen-only (unaddressable) HPIB
> interface, since the plotter can send data back to the 9815

Try re-reading my previous replies. You're making it more complex than it is.
The 9815 interface connection consists merely of:
  - the 8 HPIB data lines (bidirectional)
  - the 3 HPIB handshake lines (bidirectional)
  - a reset/device-clear line
  - a static 9815-mode assertion line
  - common

In other words: un-addressed talk/listen HPIB-style data transfer.