8 May
2008
8 May
'08
12:52 a.m.
bpope at wordstock.com (Bryan Pope) wrote:
That would probably be an issue even with the ultrasonic setup, ISTR that there were
"cat chasers" in the market which issued ultrasound when something entered the
detection area of an IR sensor to prevent the fuzzball from going in places where it
shouldn't (e.g. near expensive furniture).
ard at p850ug1.demon.co.uk (Tony Duell) wrote:
I suspect if you use 'classic' modems (300 baud, 1200/75, etc), then
it'll e totally trivial if you can also modify the modem. After all,
there are separate Tx and Rx signals inside the modem unit.
Yes, but what about the levels? Phone line vs. capsule mic/handset speaker?
First of all sorry, I learnt that the correct term is "cordless phone jack".
Okay, the whole connection setup would look like that:
Comp1 === Modem --- CTJ ))) DECT Base ))) CTJ --- Modem === Comp2.
=== is RS232, --- is phone line, ))) is DECT transmission.
I don't know if that fits your needs, as the modems will probably require some
handshaking and they must be used to "dial" the connection (like from one line
of a PBX to another). The cordless telephone jacks for the Gigaset DECT system are called
"Gigaset 1000 TAE" (or, relabeled: "T-Sinus STA") in Germany, but
those have the German TAE-style phone jack.
Searching for "DECT cordless telephone jack" should bring up some hits. Beware
that some types seem to be trying to be too smart already, I read a manual for a system by
TIPTEL where you have to set a switch for fax/modem operation on the telephone jack and
the thing emits some sort of negotiation burst ("a short hissing noise") upon
pickup when in this mode.
Depending on the type, your modem may even need to generate a flash or ground flash signal
to put the CTJ into internal dialling mode (don't seize the line at the base station,
but ring up another CTJ/handset). With the Gigaset/T-Sinus part you make the distinction
by dialling either 0 for external or 9 for internal before the number.
Asking beforehand helps a lot I would think ;) At our house, I use every chance when
wiring is touched to bring Cat5, RG58 and 2-4 pairs of undedicated copper to pretty much
every room - the coax for 10b2 or CCTV, the copper for RS-232, audio, IR-remote-by-proxy,
phone or whatever future needs arise.
If you can
stand hearing 1070Hz, 1270Hz, 2025Hz, and 2225Hz tones,
and you're not making too much noise, howzbout: implement Bell 103
with modems with microphones and speakers, and just skip the whole
interconnecting wire business (...)
I think the cat(s) would take issue with that and proceed to destroy
the cause of said tones... It shouldn't be too hard to use a C/L phone as the
wireless link=20
between two modems.
I'd be very interested in such an arrangement, but I have the
suspicion that there will be no convenient location in the handset's
circuitry to interface a phone line to. For the DECT
system anyway, there are things called "cordless phone
sockets"; they aren't really cordless as they need a wall wart, but
they are learned to the base station like a new handset is and present
Mains is not a problem , given that many of my classic computers also
need it ;-) I see it's
hard to make do without permanent cabling, but the ports
shouldn't be such a problem. You could just run two links into each
room where
So I wait for my parents to go out, when they get back they see DB25
sockets on the walls of most of the rooms :-). If the 2 machines are next to each other, I might just
run a null-modem
cable between them ;-)
I was well aware of that option :) but two links would, for example, enable you to connect
two machines which are in the same room, but need protocol analysis or conversion between
them done by a third device in a second room.
Cheers,
Arno
--
Arno Kletzander
Student Assistant // Studentische Hilfskraft
Informatik Sammlung Erlangen
www.iser.uni-erlangen.de
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