1964 Antique MODEM Live Demo

[Fred Cisin]

> > We saw him dial, and put the handset into the cradle, but he did NOT
> > shut the lid.  The notch is there for a reason.  If you don't close
> > the lid, ambient noise, such as a nearby printer or 026, can be a
> > problem.
> Chuck wrote:
> > Yeah Fred, but a modern laptop isn't nearly as noisy as an ASR33!  I
> > don't recall Silent 700 terminals having any such lid on the acoustic
> > coupler.
> Many ASR33s were equipped with an acoustic coupler to the right of the
> keyboard and printer, and they didn't have any cover to exclude outside
> noise.  They worked fine even though the ASR33 itself was quite noisy,
> because 103 FSK modulation at 110 baud [*] had a lot of noise margin.

Yes, many other acoustic modems functioned without a cover.
The Livermore Data Systems model A had sound deadening foam (subject to
the usual deterioration) on the underside of the lid, and needed it a lot
more than some other modems.