RE: Phone Switches + telephone banking etc

[Jacek Lipkowski <sq5bpf () acid ch pw edu pl>]

On Fri, 7 Jun 2002, Kayne Ian (Softlab) wrote:

> Why's that? I've never heard of a bank making that statement. A cordless
> phone is pretty much a minor risk anyway, if someone wanted to go to the
> trouble of listening in to your call to the bank, they'd be better off
> splicing the phone line outside your house. IIRC DECT fones are scrambled in

this situation is similar to ethernet - would you rather tap wires (even
if they were outside the building), or listen for accesspoints within the
area?

> some way, so you can't just tune in with a reciever. Non-DECT fones have

just because it's digital, doesn't mean you can't listen to it :)
unless it's encrypted of course.

> enough trouble finding the base station and making a clear call through even
> paper thin walls, so someone sitting outside your house is unlikely to get
> anything through a few layers of concrete...

i wouldn't be so sure. once upon a time people used phones that transmited
49MHz from the set and 46MHz from the base station. using a cb radio
receiver and a simple home made converter i could listen into the base
station from very far away. on a 1/4 gp antenna i could hear a base
station from over a kilometer away (at night when the channel wasn't very
crowded). a 3 element yagi antenna improved the range even further.

the only problem with listening to cordless phones is that there are too
many on a single channel transmiting at once, so you hear only nearby
stations.

i haven't personally tried listening to 900MHz phones, but i would suspect
that they are even easier to listen to. the higher the frequency the
easier it is for radio waves to bounce around obstacles. you can also make
a directional antenna with higher gain easily.

jacek