[sci.electronics] Modem over cordless phone?

cb1p+@andrew.cmu.edu (Chris Beasley) (03/26/91)

Hlo all,
Having just purchased one of those spiffy new 5000 series
cordless phones from AT&T I am now wondering if there is a
way to hack it so I can use my modem and laptop out on the
lawn.  (later I'm going to want cellular ethernet on the cheap
but we'll get to that)
So I figure there have to be at least three ways to do it
(even though I am a novice to phone hacking, I do have some
reverse-engineering experience: I'm a reverse-engineer by trade :-))
Anyway, it seems likely that a hack on an old-style accoustic
coupler would work but not be very elegant.  The second possibility
would be to hack an RJ-11 connector into the cordless half
of the unit.  I suspect there are two ways to do this: one
involving something that works ok but is a bit of a hack and
one that actually does the thing 'right'.  The problem is that
I really don't even know what the signal specs are for the four
phone wires (I do know that you only need two for minimum functionality).
So I am wondering if anyone can enlighten me as to what the
various problems might be and how I could proceed short of
breaking out the scope and voltmeter and poking around inside
some different phone equipment?
Has anyone tried anything half this crazy?
Am I totally crazy?
Does someone make a piece of equipment remotely like this?
RSVP
Beez.

lrk@k5qwb.UUCP (Lyn R. Kennedy) (03/26/91)

cb1p+@andrew.cmu.edu (Chris Beasley) writes:

> Having just purchased one of those spiffy new 5000 series
> cordless phones from AT&T I am now wondering if there is a
> way to hack it so I can use my modem and laptop out on the

The obvious problems are that the cordless phone is four wire
and probably different impedances from you modem. Assuming you
can get the modem to do four wire, then you have to get the
levels close enough. I doubt the off-hook stuff would be worth
fooling with, you can manually turn the thing on and get a dial
tone. Then if your modem will dial in four wire mode, you should
be able to originate calls. Forget answering. The ringer won't
work right into a modem.

> Am I totally crazy?
> Beez.

Yes (since you asked) :-)
But let us know if you succede.


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Lyn Kennedy      K5QWB @ N5LDD.#NTX.TX.US
                 P.O. Box 5133, Ovilla, TX, USA 75154

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