In article , Dave Plowman (News)
wrote:
The Compact Cassette was introduced as a mono format for dictation
machines, etc. Philips were sensible enough to allow it to be used under
license but free of charge. But did retain a degree of control over the
basics.

I'm not sure if this included the use of Dolby B or not. But did over
the basics like speed.

IIRC They mandated aspects like the physical dimensions (inc. things like
track widths and spacings), but I'm not sure about which 'electronic'
details they might have defined or limited.

They did try to flog their own 'noise reduction' (DNS?) system which was
single-ended. But I don't recall that they could (or attempted to) block or
control the adoption of Dolby. If nothing else, they couldn't have stopped
anyone from buying a Bolby adaptor box, anyway! Given how good Dolby was
they probably twigged quite quickly it would be good for sales, and hence
their own deck/cassette royalties!

Jim

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