Stamp to modem interface
Archiver
Posts: 46,084
Ignacio-
Modems typically operate in one of two modes: let's call them
command mode and data exchange mode.
Dialing out and hanging up (or any other "AT" command action) must
occur while the modem is in command mode. Info exchange occurs only
during data exchange mode. While in info exchange mode, the modem
views an "AT" command at simply text to be transmitted rather than a
command.
Going from command mode to data exchange mode happens sort of
automagically. When you dial out and a link is established, the
modem will enter data exchange mode without further prompting.
Dragging a modem from data exchange mode back into command mode is
not so simple. Typically, you pass it a specific sequence of
characters (often +++) in the data stream, then
nothing more for a defined interval of time (often ~ 1 sec). The
modem will then interpret the escape sequence as your desire for it
to return to command mode. After doing so, it will then be
responsive to AT commands, such as ATH (hang up).
If you have the manual for your modem (do they still make manuals
for modems?) it should describe the details for the above. It
should even tell you how to define the escape sequence.
This is all from memory so I've probably got something wrong, but in
general it probably applies to your question.
Regards,
Steve
On 11 Jul 01 at 13:21, Ignacio Fumanal Andres wrote:
> after dialing out (sending strings from BS2 to modem...) and after
> doing my info xchange, the line does hold on "busy" alhtough BS2
> sends out "hang" messages to modem. any idea why this happens?
Modems typically operate in one of two modes: let's call them
command mode and data exchange mode.
Dialing out and hanging up (or any other "AT" command action) must
occur while the modem is in command mode. Info exchange occurs only
during data exchange mode. While in info exchange mode, the modem
views an "AT" command at simply text to be transmitted rather than a
command.
Going from command mode to data exchange mode happens sort of
automagically. When you dial out and a link is established, the
modem will enter data exchange mode without further prompting.
Dragging a modem from data exchange mode back into command mode is
not so simple. Typically, you pass it a specific sequence of
characters (often +++) in the data stream, then
nothing more for a defined interval of time (often ~ 1 sec). The
modem will then interpret the escape sequence as your desire for it
to return to command mode. After doing so, it will then be
responsive to AT commands, such as ATH (hang up).
If you have the manual for your modem (do they still make manuals
for modems?) it should describe the details for the above. It
should even tell you how to define the escape sequence.
This is all from memory so I've probably got something wrong, but in
general it probably applies to your question.
Regards,
Steve
On 11 Jul 01 at 13:21, Ignacio Fumanal Andres wrote:
> after dialing out (sending strings from BS2 to modem...) and after
> doing my info xchange, the line does hold on "busy" alhtough BS2
> sends out "hang" messages to modem. any idea why this happens?
Comments
after dialing out (sending strings from BS2 to modem...) and after doing my
info xchange, the line does hold on "busy" alhtough BS2 sends out "hang"
messages to modem.
any idea why this happens?
also, anybody can share source code to manage an external modem from BS2??
(i use Scott Edwards' ideas in Programming basic stamps...) but something
else would help a lot
thanks
ignacio
Original Message
From: Enigma R [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=F3TLdbNwYXCTlp2jxEOIRWnk2elI8PHL-MNlEXPwHuJY50T9f5Pw5pSBkPI7XAsK5cpWbUSlvifIOeFrYw]neweraartist@j...[/url
Sent: domingo 6 de febrero de 2000 17:30
To: stamps@p...
Subject: Re: [noparse][[/noparse]STAMPS] Stamp to modem interface
look in Scott Edwards' "Programming and customizing the basic stamp
computer." it has hookup diagrams and programs, but only for external
modems.
----> Andrew R!
On Sun, 30 Jan 2000 13:46:04 PST "ED Ward" <punk__rocker@h...>
writes:
>The BS2 can run up to 38400 buad can it not? Is there a way to read
>incoming data from a internal modem? Correct me if I go wrong here...
>tones
>from the telephone line come into the modem, they are they then
>converted
>into serial ascii stream, then to parrallel data that goes into the
>bus on
>the motherboard. I want to read the serial ascii stream into a stamp
>which
>will recognize strings of data that are typed from a keyboard. This
>would
>be easy to do on an external modem which interfaces to a serial port.
>I
>want to do it with an internal modem, is it possible? Maybe could the
>
>computer send the data from the modem out of another serial port? I
>want to
>make a device that will allow me to cheat in starcraft by seeing what
>my
>enemies are typing:-)
Ignacio
[noparse][[/noparse]Non-text portions of this message have been removed]
>question here:
>
>after dialing out (sending strings from BS2 to modem...) and after doing my
>info xchange, the line does hold on "busy" alhtough BS2 sends out "hang"
>messages to modem.
>any idea why this happens?
Ignacio -
I've seen occasions when ATH would NOT WORK, but ATH0 DOES.
No idea why <shrug>
Regards,
Bruce Bates
I prefer modem hang up via hardware. Connect a signal output from
the BS2 to the DTR pin on the modem. Configure the modem with the
&D3 command, which allows a low level on DTR to hang up and reset the
modem. That is much more reliable than the software hang-up
sequence, especially in automated systems.
Some modems will hang up automatically if the carrier is lost. There
is a configuration setting for the number of seconds to wait before
that happens. However, some modems do not hang up properly when the
carrier is lost, and noise on the line will continue to be received
as random characters that are passed through to the BS2.
Additional modem info and code:
http://www.emesystems.com/BS2rs232.htm#modem
-- regards,
Thomas Tracy Allen Ph.D.
electronically monitored ecosystems
mailto:tracy@e...
http://www.emesystems.com
>question here:
>
>after dialing out (sending strings from BS2 to modem...) and after doing my
>info xchange, the line does hold on "busy" alhtough BS2 sends out "hang"
>messages to modem.
>any idea why this happens?
>
>also, anybody can share source code to manage an external modem from BS2??
>(i use Scott Edwards' ideas in Programming basic stamps...) but something
>else would help a lot
>
>thanks
>
>ignacio
>
>
>
Original Message
>From: Enigma R [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=s_1Zc97okdUMTV1X2AkwD7ch5pmtEDJn2BCtuBlvyGwcN1u4N6S9i1htVqwwD4XZM6AIX1fxNJaaTM0]neweraartist@j...[/url
>Sent: domingo 6 de febrero de 2000 17:30
>To: stamps@p...
>Subject: Re: [noparse][[/noparse]STAMPS] Stamp to modem interface
>
>
>look in Scott Edwards' "Programming and customizing the basic stamp
>computer." it has hookup diagrams and programs, but only for external
>modems.
>
>
>----> Andrew R!
>
>On Sun, 30 Jan 2000 13:46:04 PST "ED Ward" <punk__rocker@h...>
>writes:
> >The BS2 can run up to 38400 buad can it not? Is there a way to read
> >incoming data from a internal modem? Correct me if I go wrong here...
> >tones
> >from the telephone line come into the modem, they are they then
> >converted
> >into serial ascii stream, then to parrallel data that goes into the
> >bus on
> >the motherboard. I want to read the serial ascii stream into a stamp
> >which
> >will recognize strings of data that are typed from a keyboard. This
> >would
> >be easy to do on an external modem which interfaces to a serial port.
> >I
> >want to do it with an internal modem, is it possible? Maybe could the
> >
> >computer send the data from the modem out of another serial port? I
> >want to
> >make a device that will allow me to cheat in starcraft by seeing what
> >my
> >enemies are typing:-)
>
>
>
>Ignacio