Synchronous serial Re: E-Mail Formats RE: Future of cctalk/cctech

Peter Corlett abuse at
Fri Jun 19 05:21:56 CDT 2020

On Fri, Jun 19, 2020 at 12:21:14AM +0100, Pete Turnbull via cctalk wrote:
> [...] Some of the UK banking systems like HOBS survived using viewdata that
> way up to the end of the 1990s, and I still have at least a couple of 1275
> modems.

Hobbyists are still running Viewdata BBSes. Here's one connected to the
Internet and provided with a JavaScript client so you can log in and have a
poke around:

Offering access to one's BBS via TCP/IP isn't really optional any more now that
many of us no longer have suitable analogue POTS lines to plug our old modems
into, what with a mobile being a better choice for most purposes. I think
(HS)CSD might have carried over from GSM into 3G, and it's even possible that
my tinpot telco would connect such a call, but the odds that I could convince
my mobile to make the call is pretty much zero. How do you enter AT commands on
an iPhone anyway?

Also, I resent paying per minute for low-bandwidth phone calls when I've got
unmetered VDSL.

I would write Viewdata clients in the nostalgia wave of the late 1990s and
early 2000s, as it was also a nice easy introduction into a new platform's
graphics and I/O subsystems. Maybe I'll do one in WebAssembly for old time's

> The idea was to use 1200 for the transmission from central computer to
> consumer, and the back channel for user responses/commands. Not many people
> type faster than 7.5cps.

That's 75WPM with the usual rule of thumb of six characters per word. I can
copy-type at about 75-85WPM, which would interact badly with a small FIFO on a
very basic terminal, what with that being an average and some words are typed
at a faster rate. Fortunately, I've never suffered a Viewdata terminal that
awful: the BBC Micro backed its 6850 UART and its 1-byte FIFO with a luxurious
192-byte software FIFO, for example. Having to stop for a sip of tea while the
buffer drains isn't so terrible.

Normally one would compose longer bits of text offline, of course, so that BT
would get the smallest pound of flesh possible. Definitely a company with the
"never mind the quality, feel the price" mentality, but that's all telcos for

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