Simulated telephone

Fred Cisin cisin at
Wed Aug 25 23:02:58 CDT 2010

On Tue, 24 Aug 2010, Brent Hilpert wrote:
> If both modems in a given connection are older ('80s), lower-speed
> (300-1200/2400) it will likely work by simply connecting them together
> and commanding one off-hook in answer mode (ATA ?), then the other
> off-hook in originate mode (ATD ? ATH1 ?). I have successfully done
> this with particular modems up to 14.4Kbps but might be forgetting the
> commands.

Many of my older modems are from BEFORE "Hayes Compatible" became the
standard for giving commands to the modem.

BTW, Joe Campbell ("RS232 Solution", "C Programmer's Guide to Serial
Communication", etc.) got hired later by Hayes to document just what the
Hayes "standard" consisted of, because there were numerous variation in
commands between Hayes' own modems!

Grumpy Ol' Fred     		cisin at

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