Feature request for vgetty

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Hi!

Tony Scholl wrote:
> Marc Eberhard wrote:
> [...]
> >The problem is, that this is at least in Germany not allowed by law.
> >The modem mustn't pick up the line without a ring signal coming in
> >from the telco line. Only exception is a dialout by the modem itself.
> 
> Without doing any patching, how about simply listening to the log
> file and sending SIGUSR1 to mgetty/vgetty? Something like

Exactly the very same problem. It will not work with approved modems
in Germany for the same reason. Vgetty will try to pick up the phone,
but the modem will return ERROR. And that's it: The end.

> Actually I have thought for some time about a slightly different
> feature - that vgetty would pick up the phone if it hears a
> certain DTMF sequence. This is what my traditional fax machine
> does - if I answer a call and hear the fax tone, I can key in the
> code and the machine picks up the line, instead of having to run
> downstairs... can vgetty detect DTMF at that stage of things?

As I explained, this is at least in Germany not _allowed_ by law. So
your fax machine probably has no approval for Germany. But apart from
that, I also haven't seen any non-German-approved modems (like US
ones), that allow listening to the line without picking up the phone.

Would be interesting to know, if anybody on the mailing list has seen
such a piece of hardware. Anybody?

So the sad answer is: What you want is forbidden in some countries
and at least I am not aware of any modem supporting this feature in
countries where it is allowed. The reason might be, that the layout
for most modems is in such a way, that the modem circuits are
connected to the telco line by a single relais. If the relais is
open, the modem circuits are not connected to the telco line, if the
relais is closed, the modem has picked up the phone. It's handled by
the same relais. So there is no way to listen into the line without
picking up the line. Of course one could do such a thing with a
different design, but not with that conventional layout for modem
hardware. And then the manufacturer would run into the problem, that
this hardware cannot be sold in all countries. So that company would
need at least two different kinds of hardware. Maybe that's the
reason?

Bye,
Marc
_______________________________________________________________________________
Email: Marc.Eberhard@Poseidon.ThPhy.Uni-Duesseldorf.DE
WWW:   http://Poseidon.ThPhy.Uni-Duesseldorf.DE/~marc/
PGP:   http://Poseidon.ThPhy.Uni-Duesseldorf.DE/~marc/Marc_PGP.key

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