PDP 8/L console

From: David Gesswein <djg_at_drs-esg.com>
Date: Thu May 18 21:16:47 2000

>From: Lawrence LeMay <lemay_at_cs.umn.edu>
>My PDP 8/L that I recently acquired, has a cable that i assume is for
>the console terminal. It has a 9 pin male connector with only pins
>1 through 6 present. Is this a standard serial connection? This was
>a papertape based system, so it may have been connected to a teletype
>ASR 33. Will I need to locate something that can do 110 baud to use
>as a console?
>
If it is the W076 on the other end of the cable it is a teletype.
It normally runs at 110 baud current loop. You can either create an
external RS-232 to current loop or make a new W076 to do RS-232.
If you want to cheat you can reduce the capacitor on the M452 to increase
the baud rate. The serial port is not double buffered so you may have
problems with overruns when sending tape images to the 8/L. I think
the BIN/RIM loader is fast enough but Focal is not. On the teletype the
data was held off by the reader run signal.


>Also, I'm very curious about the other cables comming from the 8/L...
>I have 6 flat black cables, similar to ribbon cable but thicker, with
>9 'wires' on each cable. possibly each 'wire' is something similar
>to coax, but i'm not sure... Each pair of these ribbon-like cables
>go together into a centronics 36 pin male connector. thus there are
>3 centronics connectors, which are labeled: "A D36", "B D35", "C D34".
>Any clues as to what this might be for?
>
Peripherals. This extends the 6xxx instructions to external equipment and
allows the external equipment to do 1 and 3 cycle databreaks (DMA). With
6 cables only programmed IO is supported, 10 or 11 are required for databreak.

The labels are the location they plugged into the the peripheral. I
think most DEC stuff like the DF32's I have on my 8/I use Flip chip
connectors on both side so it may of been a third party peripheral.

David Gesswein
Received on Thu May 18 2000 - 21:16:47 BST