TELECOM Digest OnLine - Sorted: Re: History of Hayes Modem

Re: History of Hayes Modem

Robert Bonomi (
Sat, 14 Jan 2006 23:24:11 -0000

In article <>, Al Gillis
<> wrote:

[[.. munch ..]]

> Acoustic Couplers pretty much topped out at 300 bits per second. The

Don't tell Racal-Vadic about that!

They had a 1200-bps ACOUSTIC-COUPLED modem on the market in the 70's.
Anderson-Jacobsen even licensed it, and made similiar units under
their own label.

No, it was *not* "bell-212" compatible. It used the propietary Vadic
3400 tones/encoding scheme.

Worked *way* better than Bell 212, which suffered from the fact that
the Tx and Rx frequencies were exactly one octave apart. $DIETY only
knows what Bell labs was thinking when they did _that_.

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