> On Feb 13, 2025, at 6:54 PM, Henry Bent via cctalk <cctalk@classiccmp.org>
> wrote:
>
> On Thu, 13 Feb 2025 at 18:44, Rick Bensene via cctalk <cctalk@classiccmp.org>
> wrote:
>
>>
>> There was a company called Xircom that made parallel port modems. These
>> were full modems that were small enough that they plugged into a laptop
>> serial <parallel> port, and got their power from the laptop via the
>> external mouse/keyboard port. They had a feed-though connector so you
>> could still connect and external mouse/keyboard if you wanted. ...
>>
>
> 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; I unfortunately had a
> parallel port ZIP drive and it was a dog.
>
> -Henry
The later parallel ports include several faster modes than the original one.
The best of these is "EPP" mode which is fully bidirectional, with interlocked
high speed handshakes. I think you can get fairly close to (original)
Ethernet speeds with those. I once built a software-defined radio using one of
those for its baseband data/control interface, it worked quite well. The state
machine fits in a small CPLD (Lattice isp2032).
paul
