Date   : Mon, 30 Apr 2007 21:54:20 +0100
From   : BBCMailingList@... (Ian Wolstenholme)
Subject: Tone Dialling Frequencies

I'm sure this should be possible, but I can't get
it to work - can the BBC sound chip generate
the frequencies used for tone dialling on telephones?

I've got the list of frequencies for the numbers
and the sound chip data sheet but I can't get any
output which sounds like the right notes.  I think
I may be going wrong somewhere with the divide
by 4000000 bit.

Can anyone point me in the right direction, or even
write a bit of code to do it?

The dial on the BeebMaster GPO telephone gave up
a few years ago and since then I've been using a
little tone generator number pad thing but it's finally
given up as well so I either get wrong numbers or
that lady telling me I've mis-dialled!  I thought it
would be good if I could get one of my Beebs to
do it!

Best wishes,



Ian