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Posted by jim on September 15, 2006, 9:22 am
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Thanks a lot for response. I also post my question to comp.dcom.modems.
In fact, I use another laptop(hyperterminal is set up as 1200 8-N-1, no
protocol, no data compress) dial my IBM laptop, connection was set up
at 1200, 8-N-1. I also can dial from my IBM laptop to dial old host to
stablish connection. I am sure their no password at all. My laptop send
carrier out for sure, I can see it on scope and i can hear the modem
noise. I am going to make the device modem as an answer to see what
happen.
Thanks again.
GlowingBlueMist wrote:
> jim wrote:
> > Hi all,
> >
> > I am using IBM T40 laptop with modem Agere systems Ac'97. I am using a
> > device as a remote modem to dial in an try to stablish a connenction
> > at 1200, 8-N-1, no protocal at all. I answer the call, but some how
> > can't detect carrire. but I use this device to dail an old host, they
> > can go throught. My init string is "AT&FE0B0N0Q0W1X6&Q6S7=150S0=2\r".
> > I
> >
> > traced the phone line, if the deviceconnect to old host the trace is:
> >
> >
> > DCE [ R O R ] [ R N G ]
> >
> >
> > DTE 80 B2 SP D2 BS AK " A
> > 82 80 SP VT A8
> >
> >
> > DCE [A T C ] [ A T B ] [ C D F E ] EQ
> >
> >
> > but if connect to my laptop the trace is:
> >
> >
> > DCE [ R O R ] [ R N G ] [ A T C ] [ A T B ] [
> > C D F E ]
> > DTE
> >
> >
> > the remote modem does not send carrier at all. is there any
> > configuration at answer modem to effect orginal modem's carrier?
> >
> >
> > any answer or help would be appericatiaed.
>
> You might have better luck trying a note in comp.dcom.modems newsgroup but
> here goes. If possible give them the modem brand/models of both modems and
> they should be able to get you working.
>
> Yes, it is possible for some brands/models of modems to be set so that they
> do not send a carrier until they first hear your modem send a validation
> password to it during the period of initial silence. Only the person who
> set up the answering modem would know the password as there usually was not
> a "default" password built into them. Some modems can even be set to answer
> the line, hang up and then call back to the "calling" modem depending on a
> password and callback string the originating modem sends to it. I have even
> run into a situation that used the call back modem method and it would only
> call back to telephone numbers that were preconfigured into the modem.
>
> Try calling the remote modem using your telephone and see if the modem
> actually sends a carrier signal for a short time after it answers. If it
> does then the problem is most likely with the calling modem. Modern modems
> usually are set to try to connect at the highest speed and then start trying
> to connect at other slower speeds. The old 1200 baud modems tend to not
> wait around for the newer models to get down to the 1200 baud range and time
> out the call. You would need to try a dial string that first locks your
> calling modem at 1200 baud on the Telco side and then make the call. With
> luck it will then be able to talk with the older/slower modem.
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