Never read about it or seen it. Good luck.

If those games worked with modem connection to internet, their bandwidth and latency requirements are modest so you can use another PC to act as a bridge between serial and ethernet, by using SLIP or PPP.
If those games use LAN connection, most likely their bandwidth and latency requirements can't be met with a serial connection.
I'd say it is easiest to put a real ethernet card and use it for LAN and internet play.
Or use a faster PC as host for DosBox, it should provide games at least IPX and serial connections and route them through TCP or UDP between your DosBox host PCs.

You could technically do ppp over a null modem cable. SLIRP could also work.

Does the motherboard provide USB ports? If so, maybe something like this would be easier to source/find than some external RS232 network interface which might not even exist. This is cheap chinese stuff, though, so I wouldn't trust it that much, but hey, worth a try. And it DOES claim 98SE support.

There are also parallel port to ethernet adapters. That would probably work like a charm.

I tried to do something like this once but didn't finish it; I was trying to connect a Dreamcast console to my home LAN. The Dreamcast has a modem by default, and there is a very elusive and reduced-functionality broadband adapter which is very hard to find and very expensive. So I tried a internal modem->external USB modem->USB port on router->LAN configuratrion; I almost got it to work on a cheap router with USB port running OpenWRT, but got bogged down in configuration files and (mostly) getting the right timings for the USB modem to answer an incoming call and not hang up immediately.

I imagine that something similar could work in a configuration like this:
serial port->serial-to-USB converter->USB port on router->LAN
But you'd be having to work out the scripts to make it functional on OpenWRT yourself.

FWIW the router I used is a Chinese WT3020 https://wiki.openwrt.org/toh/nexx/wt3020 which can be had for about $15 on aliexpress; after installing OpenWRT on it, it's a very useful and configurable router.

Just a quick note: while adapters to connect RS232 devices to a PC through an USB port are common, I have NEVER seen anything that allows connecting USB devices to an RS232 port. And because of how USB works, I really doubt any were ever made.

alexanrs wrote:

Just a quick note: while adapters to connect RS232 devices to a PC through an USB port are common, I have NEVER seen anything that allows connecting USB devices to an RS232 port. And because of how USB works, I really doubt any were ever made.

But that is not how the above is supposed to work.

(edit) to elaborate, you would set the router so that it maintains an open serial connection through the USB port adapter continuously, whether the RS232 port on the computer provides any activity or not. When activity is detected, react to it according to script. The connection would then always be initiated from the router (USB) side.

So you are saying to use a modem that can be an USB host? (you cannot connect the USB side of one of those adapters to a device port, only a host one)

alexanrs wrote:

So you are saying to use a modem that can be an USB host? (you cannot connect the USB side of one of those adapters to a device port, only a host one)

These configurations are possible, yes... If you own a router with USB ports (generally used to connect mass storage stuff, like external HDDs), compatible with a 3rd party router firmware like OpenWrt.

Basically, you reflash your router with OpenWrt and a kernel with drivers for your USB-to-Serial Adapter. You then can connect the USB side of your adapter to Router, and configure a SLIP server with some extra OpenWrt package in the router.

That's how some retro users connect their old IBM-XT computers to Internet. There are videos about this in Youtube.

Before this goes any further I think we should rule out any USB-based solutions: my system is Windows 98 vintage and has 1.1 at best. I think the best shot would be some sort of serial-to-ethernet approach but I am concerned about bandwidth and possibly also communication protocols in that case.

BaronSFel001 wrote:

Before this goes any further I think we should rule out any USB-based solutions: my system is Windows 98 vintage and has 1.1 at best. I think the best shot would be some sort of serial-to-ethernet approach but I am concerned about bandwidth and possibly also communication protocols in that case.

USB 1.1 should already be faster than a RS232 could ever be. Don't discard it just yet. And I'm yet to find an USB 2.0 device that does not work on an USB 1.1 port. And Windows 98 will provide IPX support for DOS apps regardless of what network hardware you have without the need to load specific DOS drivers.

BaronSFel001 wrote:

Before this goes any further I think we should rule out any USB-based solutions: my system is Windows 98 vintage and has 1.1 at best. I think the best shot would be some sort of serial-to-ethernet approach but I am concerned about bandwidth and possibly also communication protocols in that case.

If you're approaching for a "plug-n-play" solution that's you just will plug and it will just work, then would be your best bet one of these serial to ethernet adapters. But these things are rare and expensive. Personally i've never seen something like that were i live. That's why the suggestion of the modded router with an USB-to-Serial adapter (with the USB side connected to the router) and a SLIP server installed in the router to attend serial connections.

hyoenmadan wrote:

BaronSFel001 wrote:

Before this goes any further I think we should rule out any USB-based solutions: my system is Windows 98 vintage and has 1.1 at best. I think the best shot would be some sort of serial-to-ethernet approach but I am concerned about bandwidth and possibly also communication protocols in that case.

If you're approaching for a "plug-n-play" solution that's you just will plug and it will just work, then would be your best bet one of these serial to ethernet adapters. But these things are rare and expensive. Personally i've never seen something like that were i live. That's why the suggestion of the modded router with an USB-to-Serial adapter (with the USB side connected to the router) and a SLIP server installed in the router to attend serial connections.

Right, I have seen those and the "converter boxes" are very pricey and geared towards the industrial market. I have also seen direct cables that clearly mate the different connector ports, but according to reviews, whether they are wired correctly to establish a seamless connection is an entirely different matter. I recall that when I was in the Guard we hooked our server laptop to diagnose a satellite receiver switch which could only connect via RS-232, and if I recall it was done using a USB-to-serial cable and generating a virtual COM port in the OS.

So I was hasty in ruling out a USB approach, Has anyone here had experience in either local or internet gaming this way? Accessing the web with an XT (or even a C64 in a couple cases I have seen) is one thing; just keep in mind my goal is strictly-focused on multiplayer for now.