VOGONS


First post, by hansor

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Hi.

This is my first post, and I don't have ANY experience with modems.

What i have:
386SX Laptop -> NULL MODEM CABLE-> SERIAL USB ADAPTER CABLE -> PC -with Virtualbox (Linux) or DOSEMU or HyperTerm

Working "networking" options:

  • 1. Linux serial console with "agetty" in Virtualbox - so I can login from DOS(term95 in Norton Commander) or Windows 3.11(Kermit, NetTerm, WINQVT, Win100. (Very easy and working).
  • 2. Setting up pppd on Linux and use mTCP on MSDOS for internet over serial (but only for few DOS applications linux telnet, ftp, arachne browser) with:
    epppd.exe COM1 9600 local
    .

Windows 3.11 apps seems to not work with mTCP.

What I would like to have:

  • I would like to use Linux pppd to emulate standard modem (9.6k) - so I could use both DOS and Windows 3.11 software without any special hacks .
    Is it possible with normal pppd on Linux out of the box, or does it require some unique software?
Last edited by Stiletto on 2020-09-03, 21:34. Edited 1 time in total.

Reply 2 of 10, by Bruninho

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https://mainframed767.tumblr.com/post/1645241 … ogether-at-last

Does it help you? It seems like you're using your linux machine as a MITM...

or you could use the DOSBOX-X fork since it has NE2000 capabilities.

"Design isn't just what it looks like and feels like. Design is how it works."
JOBS, Steve.

Reply 3 of 10, by jakethompson1

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When you run pppd on linux, it should be straightforward to write a chat script to pretend to be a modem. You'd have to experiment with exactly what the other send is sending and send "OK" etc. back in response. You have to be super careful with carriage returns/line feeds though. I've done this before so I know it works.

You need a separate TCP/IP stack for windows 3.1. Internet Explorer 3.x for Win3.x came with a free one from Microsoft. You might try that one.
Also, some ppp software, as you found, already includes null modem cable support.

Finally, it likely requires a physical linux PC with a parallel port on the other end, but have you looked into PLIP? It's much faster than 9600 serial.

Reply 4 of 10, by hansor

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Jorpho wrote on 2020-09-03, 20:17:

Would using Twinsock on Win 3.x via tshost on your Linux machine be worth considering? Or is that too much of a hack?

If its hacking on "server" side its perfectly OK. is it the same technique as in Bruninho post?

Bruninho wrote on 2020-09-03, 20:27:

https://mainframed767.tumblr.com/post/1645241 … ogether-at-last

Does it help you? It seems like you're using your linux machine as a MITM...

or you could use the DOSBOX-X fork since it has NE2000 capabilities.

I will try this method (first one)! To be honest I don't understand how come Dosbox on server side could help me here with that NE2000?
I'm using Linux inside on Virtualbox running at Windows - I simply link /dev/ttyS0 form virtual machine to COM4 (USB adapter) in real hardware, and then towards DOS laptop.

jakethompson1 wrote on 2020-09-03, 21:06:
When you run pppd on linux, it should be straightforward to write a chat script to pretend to be a modem. You'd have to experime […]
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When you run pppd on linux, it should be straightforward to write a chat script to pretend to be a modem. You'd have to experiment with exactly what the other send is sending and send "OK" etc. back in response. You have to be super careful with carriage returns/line feeds though. I've done this before so I know it works.

You need a separate TCP/IP stack for windows 3.1. Internet Explorer 3.x for Win3.x came with a free one from Microsoft. You might try that one.
Also, some ppp software, as you found, already includes null modem cable support.

Finally, it likely requires a physical linux PC with a parallel port on the other end, but have you looked into PLIP? It's much faster than 9600 serial.

Do you mean script like that: https://gist.github.com/mainframed/2300903d9c … 2ab431ca152dffc ?
As for hardware all I have is serial port AND it is limited to 9600 baud/s from laptop point of view. I tried around 20 diffrent programs and diffrent settings with ZMODEM/Kermit and 9600 is maximum realible one.

Thank you all guys for help. I will try that

Reply 5 of 10, by Bruninho

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the script I pointed out just makes the linux machine accept a connection from your dos/win3.11 machine, provided you use trumpet winsock or similar to connect. I know it works because I've done that before with a raspberry Pi 3 running that script while I connected to the internet from my modern laptop (running dos 6.22/windows 3.11 on dosbox SVN + certain custom cfg). dosbox svn does not provide internet access out of the box without something in the middle.

your real machine would've to do the same as I did with dosbox (connect with trumpet winsock or similar) to the linux machine running that script if your goal is to connect to the internet.

"Design isn't just what it looks like and feels like. Design is how it works."
JOBS, Steve.

Reply 6 of 10, by hansor

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Thank you guys!
Holy cow it worked out of BOX!

On Linux machine:

pppd ttyS0 9600 local lock passive proxyarp defaultroute noauth mtu 576 local_linux_ip:remote_dos_ip

On DOS:
1. Install Trumpet Winsock.
2. Setup connection as SLIP PPP with IP as 0.0.0.0. static IP.
3. Change the serial port to 9600.
4. Connect. It works out of the box! No need for AT commands!

Testing it now.

Last edited by hansor on 2020-09-05, 22:01. Edited 1 time in total.

Reply 7 of 10, by Bruninho

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hansor wrote on 2020-09-04, 00:46:
Thank you guys! Holy cow it worked out of BOX! […]
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Thank you guys!
Holy cow it worked out of BOX!

On Linux machine:

pppd ttyS0 9600 local lock passive proxyarp defaultroute noauth mtu 576 local_linux_ip:remote_dos_ip

On DOS:
1. Install Trumpet Winsock.
2. Setup connection as SLIP with IP as 0.0.0.0.
3. Change the serial port to 9600.
4. Connect. It works out of the box! No need for AT commands!

Testing it now.

Amazing, so you didn't need the script at all?

"Design isn't just what it looks like and feels like. Design is how it works."
JOBS, Steve.

Reply 8 of 10, by jakethompson1

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hansor wrote on 2020-09-04, 00:46:
Thank you guys! Holy cow it worked out of BOX! […]
Show full quote

Thank you guys!
Holy cow it worked out of BOX!

On Linux machine:

pppd ttyS0 9600 local lock passive proxyarp defaultroute noauth mtu 576 local_linux_ip:remote_dos_ip

On DOS:
1. Install Trumpet Winsock.
2. Setup connection as SLIP with IP as 0.0.0.0.
3. Change the serial port to 9600.
4. Connect. It works out of the box! No need for AT commands!

Testing it now.

Nice. That's what I meant by null modem support.
You may want to try and get RTS/CTS flow control working.

Reply 9 of 10, by hansor

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jakethompson1 wrote on 2020-09-04, 03:27:

Nice. That's what I meant by null modem support.
You may want to try and get RTS/CTS flow control working.

Bruninho wrote on 2020-09-04, 02:33:

Amazing, so you didn't need the script at all?

Hi guys! I made some mistake in my last posting or I was not able to reproduce my own method.

I managed to get it running again - but by choosing PPP instead SLIP in Trumpet Winsock panel, and by changing my IP to static one instead of 0.0.0.0.
All I have for now is working ping and DNS requets - but my Win 3.11 telnet client (wintel.exe) doesn't work and - and I don't have any other networking tools (I dont have Win 3.11 floppies with networking tools).

Could you recommend some simple and small (my DOS ZMODEM is limited to 9600B) Windows 3.11 telnet, ftp or http client that will work with Trumpet Winsock?

Sorry for all the chaos.

Reply 10 of 10, by Bruninho

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I will just leave this here... I just found it right now and I havent'tried it yet, but sounds very promising.
https://lunduke.com/posts/2020-06-30/

"Design isn't just what it looks like and feels like. Design is how it works."
JOBS, Steve.