Rick Bensene:

> I will try to find my Xircom parallel port Modem and Ethernet adapters in
> a box somewhere in my storage area and take a photo of them.  If I can find
> them, I’ll post a link here to the photos so those in disbelief can see
> them.


That'd be neat to see, if you do find the Xircom parallel modem.  I've seen
combo ones and their "parallel-ethernet" devices (which seem to go for
quite a premium these days), but not the modem only.  Suppose they weren't
too popular, as even laptops started to have built in modems.

These days, I do use an SDLPT, that lets you use SD-cards to transfer data
into a system over the parallel port.  I suppose that's the same general
principle (of read/writing one full byte at a time to a device).   I
haven't measured its performance yet (but would characterize it as being
comparable to a physical 3.5" floppy disk drive kind of performance - I
think copying Quake took over 40 minutes, something like that; but I'd like
to get more accurate about it, down to an actual bytes-per-second rate).
Measuring that might give me an answer on how fast something like
Laplink/Interlink cable should be able to perform.

As another experiment, I'll drop that ~7MHz 16550 serial card into a 386,
and see if I can get a 386 to push data out on RS-232 faster than 115200.
It should, but we'll see!


And I think I will do an RS-232 themed talk in June VCF, if a spot is still
open - I think I have enough now to make it interesting.   One area I'm a
little stuck on is verifying that anyone actually did make an RS-232
keyboard. Even for TV Typewriter, I'm not sure if I'd characterize that as
RS-232 related.  And Gordon Bell integrated an ASR-33 (current loop) to the
PDP-1, but might not be accurate to call that RS-232 (but can't a current
loop based thing be adapted to voltage?).  I thought the POLY-88 keyboard
was RS-232, but it'll be awhile before I can get back to that equipment.


-Steve



On Thu, Feb 13, 2025 at 6:32 PM Rick Bensene via cctalk <
[email protected]> wrote:

> Henry wrote:
>
> > I remember those, and when I went searching to look for more information
> on them I found something I > hadn't stumbled on before - apparently Xircom
> made a parallel port Ethernet adapter.  It must have
> > been pretty painful.  The parallel port wasn't a great high speed
> interface…
>
> ----
>
> Yes, I have one of those parallel port Ethernet devices too.  But,
> remember, back at that time, Ethernet was commonly 10Mb/Sec.  I think that
> 100Mb/Sec was only located in high-end datacenters and was very expensive.
> For a laptop that didn’t have a PCMCIA port, and you wanted it on an
> Ethernet network, this was an acceptable way to go.  Performance wasn’t
> great, but most of the time laptops like this were used for TELNET
> connections to other hosts on the local network for “GREEN SCREEN” type
> applications that ran entirely on the remote host.  Performance in such
> cases wasn’t nearly as much of a concern as it would be in the not too
> distant future.
>
> I will try to find my Xircom parallel port Modem and Ethernet adapters in
> a box somewhere in my storage area and take a photo of them.  If I can find
> them, I’ll post a link here to the photos so those in disbelief can see
> them.
>
> -Rick
>
>
>
> From: Henry Bent [mailto:[email protected]]
> Sent: Thursday, February 13, 2025 3:54 PM
> To: General Discussion: On-Topic and Off-Topic Posts <
> [email protected]>
> Cc: Rick Bensene <[email protected]>
> Subject: Re: [cctalk] Re: RS232 - parallel modems!?
>

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