25 Aug
2010
25 Aug
'10
11:16 p.m.
On 2010 Aug 25, at 9:02 PM, Fred Cisin wrote:
On Tue, 24 Aug 2010, Brent Hilpert wrote:
Well, I was thinking of adding in that if you have a really old modem
you might have to flip the originate/answer switch appropriately if it
has one, but I think the OP indicated he was dealing with later stuff.
(I have a couple of pre-'smart' modems, too.)
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!
The hayes command set always seemed non-sensical to me. For example,
the AT prefix on (almost) everything when you were already in command
mode seemed quite unnecessary.