[vcf-midatlantic] WiFi RS-232 Internet Modem

Paul Rickards rickards at gmail.com
Sat Jun 17 13:02:17 EDT 2017


Hi Herb,


> my impression is that this item seems to come available briefly, then get
> sold out; that may repeat or not. I'm not passing judgement, I'm simply
> reporting what I found.
>

Being one person, I only sell what I've assembled or put together as a kit.
I don't like to sit on folk's money while I work and prefer to ship things
immediately. We all know many things in life can come up unexpectedly.

I think I see one such dongle on this device, on a board that probably
> includes another processor and some RS-232 type level-converting. One could
> likely build one with an Arduino - some of them are WiFi without a shield.
> For fun, you could add a speaker to sound-out the wired-modem buzz-whirr
> connect sounds.
>

This board does indeed use a ESP8266 WiFi microcontroller and a RS-232
level shifter plus the "modem" firmware that I wrote to "glue" the pieces
together for your vintage computer.


> One challenge of vintage use of 21st century connection technology - WiFi,
> even USB/serial dongles - is how they manage both sides of the 20th century
> transfer. Translation: USB dongles have hardware buffers (and software
> drivers) that screw up character processing and other delays, by old MS-DOS
> programs and old slow microprocessors. I don't know if the WiFi dongles
> have similar issues.
>

This is certainly still a potential issue. Latency introduced over WiFi
will cause problems for things that rely on hard-wired connections to be
nearly instantaneous. I've also seen the same buffering issues you describe
with USB to RS-232 adapters. Some buffer a much larger amount than others
and seems to vary widely.

Cheers,
-p



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