Phones for Asterisk and single-pair old phone wiring?

[VirginSnow at vfemail.net]

> On Wed, Sep 3, 2008 at 12:31 PM, Ben Scott <dragonhawk at gmail.com> wrote:
> 
>   Connecting plain old telephones to analog adapters isn't an
> acceptable solution.  All the desk sets on old wiring would either (1)
> loose features beyond making telephone calls, or (2) require hook
> flash and dialing feature codes to do anything (too cumbersome for the
> users).

The problem with analog adapters is that there's no way of sending out
of band data.  (Hook flash is a temporary disruption of the channel,
which is interpereted as a signal.)  You'd might that would mean
there'd be no way of signalling functions over the line.  But there
is: in band DTMF.  And Asterisk can do it.

Asterisk has a feature called, confusingly enough, "features"
(configured in features.conf), which lets you map certain sequences of
DTMF digits to arbitrary dialplan application commands.  If you had an
"ordinary" analog telephone with "speed dial" buttons capable of
sending DTMF during a call, Asterisk could detect and act on them
without requiring any hookflashing.  You'd have to tape little
"transfer", "hold", etc. stickers on the speed dial buttons, but those
buttons would be all the user would have to see or be concerned with.
Both the local and remote users would hear the DTMF tones, however, so
this assumes that your features digit sequences aren't classified
information.

Note: if you do this, you'll want to choose digit sequences which
aren't going to be dialed by automated equipment like fax machines.
For ordinary users typing digits on the keypad, you can set the
features digit timeout low enough that it won't misinterperet user
input as feature requests (unless they type really fast!).

> Date: Wed, 3 Sep 2008 13:16:18 -0400
> From: "Kenny Lussier" <klussier at gmail.com>
> Cc: Greater NH Linux User Group <gnhlug-discuss at mail.gnhlug.org>
> >> Also, keep in mind that with Asterisk, you are not limited to SIP.
> >
> >  Right; I was simplifying for rhetorical convenience.  The VoIP side
> > of things isn't really my issue.  That's a solved problem.  :)
> 
> A solved problem is the best kind :-)
> 

No. That's a common misconception about problems.  Problems can never
really be "solved".  Problems can only ever be converted into other
problems.  The whole idea behind the art of so-called "problem
solving" is to convert problems we don't like into problems we like
better. :)

> C-Ya,
> Kenny
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