The original serial interface in the PDP-11 (later 11/20) was four cards
in a specially-wired backplane slot. There was an M782(1?) interrupt
controller, a data path module whose number I forget, and the interface.
That card brought out the cable to the outside world. IOW they were
combining existing modules to get the serial function, and adding the
interface card to connect to the outside world.
The later DL11 of course did it all on one module which fitted into an
SPC slot and had a 40-pin Berg connector on the side facing the Unibus
slots for the cable take-off.
It's been along time since I took the factory training course on the
PDP11/20, and I believe the ones I worked on in the lab at Maynard that
already had a DL11 in them.
cheers,
Nigel
Nigel Johnson, MSc., MIEEE, MCSE VE3ID/G4AJQ/VA3MCU
Amateur Radio, the origin of the open-source concept!
Skype: tilbury2591nw.john...@ieee.org
On 2022-01-02 11:24, Chris Zach via cctalk wrote:
Hm. Ok, so what was it for then? Any specific pdp11, or just the
serial plug for a weird Unibus sync modem cardset?
I'm thinking of cutting it down and using it as a 20ma current loop
plug for one of my pdp8/L's. If anyone wants to trade it for a real
DEC 8/I or 8/L card or if this thing has some sort of value let me know.
C
On 1/1/2022 8:55 PM, Bill Degnan via cctalk wrote:
On Sat, Jan 1, 2022, 7:03 PM Nigel Johnson Ham via cctalk <
cctalk@classiccmp.org> wrote:
Found here:
http://www.pdp8online.com/bklatt/43.jpg
https://www.vintagecomputer.net/browse_thread.cfm?id=249
Bill
