The whole thing seems a little bizzare to me, sending dit's and dah's down a
perfectly good voice network....but then I don't use morse code <g>

Why can't the morse key be connected to a (very) simple tone generator,
acoustically coupled to a telephone.  A matching tone decoder acoustically
coupled to the telephones ear piece would do the receiving.  It wouldn't
even have to be DTMF.  In fact, the tone detector could be just a simple
detector and comparator as long as vast amounts of static aren't a problem.
A few $'s of parts maximum, and no legality problems connecting stuff to the
telco.

A modem just seems absolute overkill in every way.

Regards

Mike Rigby-Jones


> -----Original Message-----
> From: Paul B. Webster VK2BZC [SMTP:paulb@MIDCOAST.COM.AU]
> Sent: Friday, August 27, 1999 2:38 PM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      Re: Morse Code Modems
>
> Russell McMahon wrote:
>
> > More detail would help.
>
>   As always.  From my understanding:
>
> > - Is this by telephone (???) or radio or ???
>
>   Telephone.  Paying STD rates which are now limited to $3.00 between
> 19:00 and 00:00 local.  Yes, it *is* cheaper to use the radio, but
> apparently some of these enthusiasts are actually not Amateurs!
>
> > - Describe how the overall system works.
>
>   Key and sounder each end.
>
> > - Knowing WHY this is done would be interesting.
>
>   *Not* a useful question to ask a Morse fanatic!
>
> > - The 7910 "worldchip" modem IC may still be available ([possibly
> > surplus) allowing roll yer own still.
>
>   It is a "legacy" part mostly available ready assembled inside 1200
> baud modems.  The assertion (which I find curious but...) is that these
> are becoming hard to find second hand.  I would have thought they were
> rife and to be had for nothing.  I collect them occasionally at garage
> sales, usually for a dollar or two (albeit, may have to buy the whole
> computer!).
>
> > - There are other modem IC's that would handle the data rate.
> > Depending on how this all works it may be possible to make a very
> > cheap and simple modem adequate to the task using a single tone
> > decoder IC eg LM567!!! or a 4046 PLL IC or XR... or ....
>
>   The users are nervous about hacking telecom stuff, legality, type
> approval and all that.  Besides, that involves *work*!
>
> > I am puzzled as to why a modem is needed at all unless there is some
> > arcane extra feature that you have not mentioned.  If you use an audio
> > circuit then the USER is the modem received with Morse.
>
>   Dead right.  The "arcane extra feature" happens to be the use of
> sounders for *real* Morse.  Many of these sites are historic locations
> such as Timbertown at Wauchope NSW (near here).  Now it makes sense,
> doesn't it?
>
> > If you are using eg a multipoint digital data network it may make
> > sense.
>
>   Not so easy to set up using telephone lines (as requires multiple
> lines).  I have proposed that using a contemporary modem and a
> pre-processor (e.g. PIC = On toPIC) to send a stream of ASCII events
> marked with a local clock would allow 100% faithful reproduction albeit
> with a delay (maybe 1 second or so), like Speak Freely etc.
>
>   Long breaks would allow easy re-synchronisation (a "reset" event)
> This would be readily adaptable to Internet networking and "nets" etc.
> with simple hardware.
>
>   But they (being by definition, backward-looking) say they want
> backward-compatibility with the present un-framed system which as I have
> pointed out, just isn't "on"!
> --
>   Cheers,
>         Paul B.