RS-232 Converters and ATTACH

[Thomas Lake]

I'd like to connect four serial terminals to the PiDP-11. Are the converters shown in the link below the right ones to use? If they are, which set of connectors would I wire them to?

RS-232 TTY Adapter

Also, what are the exact ATTACH commands I'd have to add to the bootstrap files for 9600,N,8,1 terminals?

Thanks for any help!

Tom L

[Mark G Thomas]

Hi Tom,

On Wed, Oct 03, 2018 at 04:56:52AM -0700, Thomas Lake wrote:
> I'd like to connect four serial terminals to the PiDP-11. Are the
> converters shown in the link below the right ones to use? If they are,
> which set of connectors would I wire them to?

> [1]RS-232 TTY Adapter

> Also, what are the exact ATTACH commands I'd have to add to the
> bootstrap files for 9600,N,8,1 terminals?
> Thanks for any help!
> Tom L

Those TTL to RS232 adapters will not help you, at least not alone, because
the Pi does not have enough additional I/O lines available to drive them
directly. You can use one for a serial console, but that would be it.

Oscar describes using USB to serial adapters, then either TTL level
converters like your link, or the optional MX232 ICs and wiring already
on the PiDP-11 PCB.

Scroll down to: "Adding 4 Serial Ports"

http://obsolescence.wixsite.com/obsolescence/pidp-11-connectivity-options

I was planning on using some CP2102 based ones that look like this:
https://www.amazon.com/KNACRO-CP2102-Module-Download-Converter/dp/B0721B3HMD

Similar can be found on e-bay for $2-$3 from China. Some have fake
CP2102 chips on them -- I am not sure if that would matter in this use
or not.

Mark

--
Mark G. Thomas (Ma...@Misty.com), KC3DRE

[Thomas Lake]

Can I use a USB hub with four (or more) USB to Serial cables?

I don't want to tie up all four of the PI's USB ports for use by terminals.

I'd still need to know how to ATTACH the ports in SIMH.

Tom L

[Thomas Lake]

I just answered my own question, I guess. I dug through my parts bins and found a USB to 4 RS-232 port converter. I plugged it into one of the Pi's

USB ports and sure enough, I now have /dev/ttyUSB0 through ttyUSB3 recognized by Raspbian. Now I just need to know how to ATTACH them to SIMH.

Tom L

[Thomas Lake]

Here are some attach statements using the DZ11 Terminal Multiplexer (DZ). I get no errors when I type these in. I haven't tested them with an actual terminal yet, however.

attach dz -V line=0,connect=/dev/ttyUSB0;9600-8n1
attach dz -V line=1,connect=/dev/ttyUSB1;9600-8n1
attach dz -V line=2,connect=/dev/ttyUSB2;9600-8n1
attach dz -V line=3,connect=/dev/ttyUSB3;9600-8n1

It's possible that the DHQ11 Terminal Multiplexer (VH) could be used instead. I haven't tried it.